John 8.31-32:
So Jesus said to the Jews who had believed him, “If you abide in my word, you are truly my disciples, (32) and you will know the truth, and the truth will set you free.” (ESV)
Jesus teaches in verse 31 that abiding in him is the prerequisite of knowing the truth and being made free by the truth. The word that Jesus uses for “abiding” in him can also be thought of as meaning “remaining” in him. John 15.4-7 are other verses where Jesus teaches us about the need of abiding in him. Abiding in Jesus can also be understood as being in alignment with him and connected to him in our thoughts and aspirations.
The action of abiding in Jesus is ongoing, continuous action, because that is the nature of the meaning of the word. But in verse 31 Jesus uses a moment-in-time type of verb, even though he could have used a form that is grammatically a continuous action verb. And in John 15.4-7, Jesus uses both types of verbs for abiding in him. So we ask, why the subtle difference? I think the verbs of moment-in-time type action are used to communicate the need for intensity and urgency. We are to take the issue of abiding in Jesus with the utmost of importance. Hence, we are to live intently focused on staying connected with, inseparable from, and in alignment with Jesus and his teaching as a pattern of life, and we are to do it with intense purpose.

