John 3:16 has been cited a number of times already. Perhaps we need to consider the meaning of the words in the original language. In the NKJV it reads as follows:
16 "For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
(NKJV)
The word "believes" is a present tense participle. The present tense in Greek indicates not single act but continual action. If John had meant to say a person need only exercise faith once in his life and salvation would be forever guaranteed he would have used the aorist tense. He used the aorist tense of the verb "gave" because God's act of giving the son occurred only once. When he speaks of believing (or having faith) he uses the present tense indicating that the promise of eternal life is for those who "believe and continue to believe. The verb "should not perish" by contrast is in the subjunctive mood which makes it a hypothetical future state. The fact that it is hypothetical does not make it uncertain. It simply means that being in the future it has not happened yet. Also, the word "perish" is presented in the Middle Voice meaning that the person is both an instigator and a recipient of the action. In this case it means that the one who believes will not "cause himself to perish." Some here claim that damnation like salvation is wholly an act of God. This scripture says, essentially, that unbelievers
cause their own destruction. The word "have (everlasting life)" is also in the subjunctive mood indicating that this final state of inheriting eternal life is potential but not actual. He is not saying we will certainly have it but that we will providing certain conditions are met, the condition being ongoing faith in Christ. Lest you think I have misrepresented these words let me present the opinion of Daniel B. Wallace, Professor of NT Greek at DTS who translated the present participle of
believe in John 3:16 as "everyone who
continually believes (Greek Grammar Beyond the Basics, p. 620.).
Greek scholar and linguist A.T. Robertson adds the following:
That whosoever believeth may in him have eternal life (ινα πας ο πιστευων εν αυτωι εχηι ζωην αιωνιον — hina pas ho pisteuōn en autōi echēi zōēn aiōnion). Final use of ινα — hina with
present active subjunctive of εχω — echō
that he may keep on having eternal life
[Robertson's Word Pictures in the New Testament
http://www.biblestudytools.com/commentaries/robertsons-word-pictures/john/john-3-15.html]
Eternal life is not a single transaction or a one-time deposit. It is an ongoing process of walking with and knowing God (John 17:3).
Jesus explained how eternal life works to the woman at the well:
10...If thou knewest the gift of God, and who it is that saith to thee, Give me to drink; thou wouldest have asked of him, and he would have given thee living water.
13 Jesus answered and said unto her, Whosoever drinketh of this water shall thirst again:
14 But whosoever drinketh (i.e. takes a drink)of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.
(KJV)
John 4:10,13,14
Jesus was focused on the moment when she would take a drink of the water of life but that would not be a one-time event for the water would become a spring of flowing water "springing up" unto everlasting life. It generates an internal connection with the living God. The one drink sets in motion the process that is called eternal life. The well will continue to flow so long as the channel remains open. If it is filled with rocks (as the inhabitants of the Land did to the wells of Isaac) the flow can be hindered or even blocked. However if we continue to believe in Him, however He will continue to supply us with life. Eternal life is not something separate from Him. He is our life and knowing Him experientially (
John 17:3) is our experience of eternal life. Our responsibility is not to earn salvation because that is impossible. We are supposed to abide, remain and continue in the flow of life that comes from the Vine to (
John 15:4,6).