Dallas Willard sometimes refers to these sorts of Christians as “Vampire Christians” because the only want enough of Jesus’ blood to get them out of hell, but they don’t have any intention whatsoever of actually obeying Jesus or following His teachings in their daily life. This kind of faith isn’t true faith at all, and anyone who embraces this shouldn’t call themselves a Christian. Why? Because a Christian by definition is follower of Jesus. Those who hope to say a prayer and invoke its power like a magic incantation to escape judgment are the same who will stand before Christ on that Day and hear the bone-chilling words, “Depart from me, I never knew you,” from the mouth of the Jesus they refused to follow.
If we are in Christ we have life. Without Christ we have no life in us. If you leave Christ, you leave salvation behind.
“Remain in me, and I will remain in you. No branch can bear fruit by itself; it must remain in the vine. Neither can you bear fruit unless you remain in me. 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 15:4-5
The statement that Jesus makes is to His disciples, not to the average bystander. He's warning them that they could possibly become detached from Himself. As Paul alludes to when he returns to this same metaphor of vine and branches being grafted in: