We can sum up Christianity in one phrase: Abide in Christ. This is what Jesus taught his disciples in the gospel of John 15:5-6 “I am the vine; you are the branches. If you remain in me and I in you, you will bear much fruit; apart from me you can do nothing. If you do not remain in me, you are like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned”.
Apostle John in his epistle is emphasizing the same point in 1 John 2:28-29 “And now, dear children, continue in him, so that when he appears we may be confident and unashamed before him at his coming. If you know that he is righteous, you know that everyone who does what is right has been born of him”.
What does it mean to abide in Christ? The word abide means to dwell, continue, stay, rest in or upon. It is being set and fixed and remaining there. It is continuing on and on in a fixed state, condition or being. Therefore to abide in Christ means;
 to continue and stay in Christ
 to sojourn and rest in and upon Christ
 to be set and fixed in Christ and to remain in Him
 to be at home in Christ; to find our permanent home in Him and to be settled in Him
There are a eight things a believer needs to do to ensure that he is at home with Jesus (abiding in Christ).
1) Must confess that Jesus is the son of God. “If anyone acknowledges that Jesus is the Son of God, God lives in them and they in God. And so we know and rely on the love God has for us. God is love. Whoever lives in love lives in God, and God in them” (1 John 4:15-16)
2) Must walk and fellowship with Christ. “Whoever claims to live in him must live as Jesus did”. (1 John 2:6)
3) Must open your life to God all the time, confess all known sins and walk in the light. “If we claim to have fellowship with him and yet walk in the darkness, we lie and do not live out the truth. But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin. If we claim to be without sin, we deceive ourselves and the truth is not in us. If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness. If we claim we have not sinned, we make him out to be a liar and his word is not in us”. (1 John 1:6-10)
4) Must continue in the word of Christ and know the truth. “To the Jews who had believed him, Jesus said, “If you hold to my teaching, you are really my disciples. Then you will know the truth, and the truth will set you free.” (John 8:31-32)
5) Must bear fruit and live a fruitful life. “I am the vine; you are the branches. If you remain in me and I in you, you will bear much fruit; apart from me you can do nothing”. (John 15:5)
6) Must dwell in love, unity, and fellowship with all other believers. “that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me. I have given them the glory that you gave me, that they may be one as we are one— I in them and you in me—so that they may be brought to complete unity. Then the world will know that you sent me and have loved them even as you have loved me”. (John 17:21-23)
7) Must experience continuous presence and anointing of the Holy Spirit. “As for you, the anointing you received from him remains in you, and you do not need anyone to teach you. But as his anointing teaches you about all things and as that anointing is real, not counterfeit—just as it has taught you, remain in him. (1 John 2:27)
Brethren, let us abide in Him who died for us.