John 3:36
36 He that believeth on the Son hath everlasting life: and he that believeth not (ESV: "does not obey") the Son shall not see life; but the wrath of God abideth on him.
The Grace New Testament Commentary - John 3:36
3:36 The expression "he who does not believe" in v 36b translates the participial construction ho apeithōn (lit. "he who does not obey"). Failure to believe in Jesus was disobeying the Father who sent Him. Hence "he who does not believe" is a good paraphrase. To gain eternal life one must obey God's command to believe in His Son. The one who does not believe "shall not see life" (cf. John 3:3, 5 where seeing the kingdom of God equals entering into it). Not only that, but he currently is experiencing "the wrath of God" (cf. John 3:18).