What does John 5:24 mean?
The word amēn is taken directly from older, ancient languages such as Aramaic. It survived in New Testament-era Greek and in modern languages as well. It is often given a literal translation of "truly," or something similar. Using this word at the end of a sentence is a way of emphasizing truth, or hopefulness. This is why we often end prayers with the word "amen." Used at the beginning of a statement, however, it means something hugely different. In that culture, Jesus' use of "Amēn, amēn, legō hymin…"—"truly, truly I say to you"—means He professes absolute, first-hand, personal knowledge. This is not something He has learned or been taught. Rather, this is a fact He knows personally to be true.This interlocks with His previous statement (John 5:23). Those who accept Christ are accepting God. That means accepting eternal life. Rejecting Jesus means rejecting God. Those who reject God are under His judgment (John 3:36). Jesus' power over spiritual life and death is proven, in part, by His power over physical life and death (John 20:30–31).
Jesus used words which place this eternal life in this moment—in the present. That is, those who put trusting faith in Christ have eternal life, right now. Their passing from "death to life" has already happened. This description of passing from death to life is only used in the New Testament by John, and only in two places. One is here, the other is in 1 John 3:14.