Whosoever believeth that Jesus is the Christ is begotten of God: and whosoever loveth him that begat loveth him also that is begotten of him. Hereby we know that we love the children of God, when we love God and do his commandments. For this is the love of God, that we keep his commandments: and his commandments are not grievous. (1 John 5:1-3)
"But a danger exists on the other side. It may be, that we love the brethren because they are pleasant to us; they furnish us with agreeable society, in which our conscience is not wounded. A counter-proof is therefore given us. "Hereby we know that we love the children of God, if we love God and keep his commandments." It is not as children of God that I love the brethren, unless I love God of whom they are born. I may love them individually as companions, or I may love some among them, but not as the children of God, if I do not love God Himself. If God Himself has not His true place in my heart, that which bears the name of love to the brethren shuts out God; and that in so much the more complete and subtle manner, because our link with them bears the sacred name of brotherly love.
"Now there is a touchstone even for this love of God namely, obedience to His commands. If I walk with the brethren themselves in disobedience to their Father, it is certainly not because they are His children that I love them. If it were because I loved the Father and because they were His children, I should assuredly like them to obey Him. To walk then in disobedience with the children of God, under the pretext of brotherly love, is not to love them as the children of God. If I loved them as such, I should love their Father and my Father, and I could not walk in disobedience to Him and call it a proof that I loved them because they were His." ~J.N. Darby on 1 John 5
that which we have seen and heard declare we unto you also, that ye also may have fellowship with us: yea, and our fellowship is with the Father, and with his Son Jesus Christ: and these things we write, that our joy may be made full. (1 John 1:3-4)
In Christ we can have blessed fellowship. Our fellowship with other believers is because of our fellowship with the Lord. When we come to Christ He brings us into fellowship with Himself and the Father, as we are cleansed from sin and made righteous with the righteousness of Christ alone. He gives us His Spirit and we have an inner "supping with Him" and He with us.
Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me. (Revelation 3:20)
Jesus answered him, "If anyone loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him. (John 14:23)
That fellowship is based on a mutual love and obedience to the Lord and a mutual indwelling of God by His Spirit. It is never based on certain goals and motives we may have in common in this world or likes and dislikes, or political views, or anything of the flesh. True fellowship in God, is based on His fellowship with us, through the mutual salvation He alone gives through His grace by faith in His finished work on the cross. We may think we are loving with God's love and fellowshipping with those who are of other religions, trying to ignore God's Word and truth and compromising in order to agree on what we can agree on, but this is fleshly humanistic "fellowship" and not the love that God alone can put in the hearts of His true children. John, in his letter of 1 John, speaks of many things that prove the true love of God in a child of God and how it looks when acted on and lived by. There are marks of those who are His children and walk in His love. Such love produces the righteousness of Christ in a person's life. If they don't have that, they are still walking in darkness and blindness (1 John 2:9). There is no way our flesh can produce that kind of love. That kind of love is only a result of His Spirit living in us and our abiding in Him in obedience to His Word, by faith in Him and all He said. It is only a result of true fellowship with our Lord.
Today there is a counterfeit "love" and a counterfeit "fellowship" that a counterfeit church preaches, by accepting all the sin and worldliness and false religion in one another and find some common ground to agree on, so they can fight for a common good. This kind of "love" says to accept sin, do not judge it, do not discern what is of God and what is not or try to admonish, rebuke, or expose what is false, in love, or do not try to hold to God's Word because that will bring division, and do not do anything that will offend, least of all preach the Word of God in truth. It says, do not tell someone they are a sinner and in dire need of the sacrifice of Christ on the cross for salvation, and that they are in need of repentance for deliverance of sin. But Jesus tells us there is no fellowship with darkness, and indeed these things keep a person in darkness, where they never are able to see His true light. They are never able to escape those very sins that keep them there and cause all the problems they have in the world, and which are the reason for the evil in this world and worst of all, which will separate them from God and His love for all eternity. Jesus tells us we cannot have fellowship with this kind of darkness if we walk in fellowship with Him. He came to destroy the works of darkness, and to set men free.
Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness? What accord has Christ with Belial? Or what portion does a believer share with an unbeliever? What agreement has the temple of God with idols? For we are the temple of the living God; as God said, "I will make my dwelling among them and walk among them, and I will be their God, and they shall be my people. (2 Corinthians 6:14-16)
We have a blessed and wonderful fellowship with God when we become born again, and as we learn to walk in that fellowship day by day continually, we have a blessed fellowship with one another in Christ that causes us to desire His will in ourselves as well as in those we love of the family of God. It grieves our hearts to see our brothers and sisters stumbling into sin, because we love them as God loves them. It grieves our hearts to see someone led astray into false teachings, because we love the truth of God's Word, and understand the importance of that true light in our lives and desire the same truth and love and obedience to the truth in their lives for them, for God's glory and for their own sake as well. Our joy together is made full. When we are together enjoying the fellowship of His truth, we delight in each other and in God. Others see that light as well, and His love is manifested through us to the world.
When there is true fellowship with one another in Christ, the whole body is able to grow up together and is protected from outside forces of evil that would come in and corrupt the church. If a root of bitterness is allowed in the church and love does not take care to stop it, it will grow and poison the whole body.
See to it that no one fails to obtain the grace of God; that no "root of bitterness" springs up and causes trouble, and by it many become defiled; (Hebrews 12:15)
Adam Clarke in his commentary states: "The root of bitterness is here used metaphorically for a bad man, or a man holding unsound doctrines, and endeavoring to spread them in the Church."
Jamieson, Faucett and Brown commentary states, "Root of bitterness comprehends every person (compare Hebrews 12:16) and every principle of doctrine or practice so radically corrupt as to spread corruption all around. The only safety is in rooting out such a root of bitterness."
If we love the Lord, Jesus says we will obey His commands to believe in Him...His whole Word and counsel, and walk in obedience to it, by loving our brethren. If we do so we will have fellowship with Him. We cannot have fellowship with Him if we are walking in sin, according to John's letter, which is inspired of the Holy Spirit, and if we say we do then we're a liar. If we are walking in true fellowship with Him in His light that light will also produce true fellowship and love with our brothers and sisters in Christ which will cause us to act as Christ would act when we see sin or departure from the truth with them. It will strive to keep that fellowship in tact with a love that will put the spiritual well-being of others, and the glory of God before our own well-being. It will be willing even to be rejected in order to try to keep another in the fellowship of the Lord. It will speak the truth in love for the sake of that fellowship.
A counterfeit "fellowship" seeks to not offend in order to maintain good feelings with another, rather than to bring one to the true fellowship that is with the Father and with the Son. This is a hard lesson for us. It is hard to learn to speak the truth in love to one another. It means a denying of ourselves. None of us wants to step on toes of another. None of us likes confrontation. And there is a place to wait for the Lord to show a person and to be patient, remembering the Lord's longsuffering patience with us as He dealt with us, but there are times when the Lord calls on us to speak up in love, sacrificing ourselves and risking rejection or confrontation. There is a time when we simply have to wait on the Lord to work in a person's heart to reveal truth that they have not the maturity yet to understand in the Lord, being an example, praying for them, speaking the Word of truth when He brings opportunity and in grace and humility, and there is a time when open rebuke needs to be done, also in grace and humility with love, seeking their restitution with the Lord. There is also a time when fellowship with another has to be broken because of sin unrepented of, or heresy or divisions they cling to and refuse correction for - also for their hopeful restitution to the Lord. How do we know which is the case?
We know because we are abiding in His Word, and in His fellowship, being obedient to it, allowing Him to correct and teach us, and fill us with His Spirit each day and motivate us by His love. If we walk in His light, His light will lead us and teach us by that "unction" or "anointing" He has given us...His Holy Spirit.
Let what you heard from the beginning abide in you. If what you heard from the beginning abides in you, then you too will abide in the Son and in the Father. And this is the promise that he made to us—eternal life. I write these things to you about those who are trying to deceive you. But the anointing that you received from him abides in you, and you have no need that anyone should teach you. But as his anointing teaches you about everything, and is true, and is no lie—just as it has taught you, abide in him. And now, little children, abide in him, so that when he appears we may have confidence and not shrink from him in shame at his coming. (1 John 2:24-28)
We learn to grow in our fellowship with Him and His love, and as we do we learn to grow in our fellowship and love with one another, and His Spirit in us teaches us and leads us into His love more and more. The more that love fills and motivates our lives, the more jealous and protective we are of that true fellowship with God and others. We can test our motives by the love of God shown us in His Word. If we are not walking in the light of His Word and His love, then we surely cannot help another to come into that light.
May the Lord work in each of us, that wonderful love and fellowship, bringing us to perfection! I will close with a wonderful prayer of Paul.
For this cause I bow my knees unto the Father of our Lord Jesus Christ, Of whom the whole family in heaven and earth is named, That he would grant you, according to the riches of his glory, to be strengthened with might by his Spirit in the inner man; That Christ may dwell in your hearts by faith; that ye, being rooted and grounded in love, May be able to comprehend with all saints what is the breadth, and length, and depth, and height; And to know the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God. Now unto him that is able to do exceeding abundantly above all that we ask or think, according to the power that worketh in us, Unto him be glory in the church by Christ Jesus throughout all ages, world without end. Amen. (Ephesians 3:14-21)
If you are not sure you have eternal life, if you want to know more about salvation through Jesus Christ, and how you can be sure, you can read more about it here.