He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life, but the wrath of God abides on him. (John 3:36, NKJV)
It is unfortunate the King James translators in 1611 used “believeth not” in the second part of this sentence. The New King James version followed suit, using the more modern, “does not believe.” But, the word in the Greek manuscript is apeitheō, which means “disobey” (BDAG), as in Romans 2:8 where the KJV and NKJV translate it, “do not obey” the truth. When the word is thus translated, John 3:36 takes on a whole new meaning: “Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him” (John 3:36, ESV, see also, NASB). Obedience is necessary to have everlasting life. Since the one who believes in the Son has eternal life, but the one who does not obey the Son “shall not see life,” we properly conclude that believing in the Son takes more than faith alone. Surely this why Jesus said, “But why do you call Me ‘Lord, Lord,’ and not do the things which I say?” (Lk. 6:46) Believers obey Jesus. Those who reject Him are “disobedient (apeitheō) to the word” (1 Pet. 2:7, 8). Demons believe, but faith alone will not give them eternal life (Jas. 2:19-20). Those who believe in the Son have everlasting life precisely because they trust and obey Him. The disobedient shall not have life, but punishment (Matt. 25:46). Have the faith to obey Jesus, and you will see everlasting life.