Its a given that scripture says whosever believes hath eternal life Jn 3:16
16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
That whosoever believeth in him should not perish, but have eternal life.
And of course this is so true. Yet how does a spiritually dead sinner change from being a unbeliever and hater of God naturally, into a Believer who begins to Love God, the True God ? The answer is by Sovereign Grace, they believe because of Grace Acts 18:27, they also believe because of Election Acts 13:48, even Election is of Grace Rom 11:5-6. A mans believing totally due to Gods Grace 1 Pet 1:21. Hasnt it been said that " No man can come to Jesus except it be given " Jn 6:65
65 And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father.
The word given didōmi means to bestow as a gift ! This being the case, it goes without saying, nobody can believe in Jesus unless its given to them by Gods Gift of Grace. See Phil 1:29
Everyone who believes in Him shall have eternal life.