In addition to saying that the believer has everlasting life the moment he believes, Jesus adds the promise that he shall not come into condemnation; that is, the sentence of sin will never be put on the believer again.
Why God should choose the meanest, basest, most unworthy individuals with absolutely nothing to commend them at all to God, except their miserable, lost condition, and then exalt them to become the sons of God, members of the divine family, and use them for His glory, is beyond all reason and human understanding. Yet that is grace.
Jesus, as He was going up the hill, fell beneath the load. Loss of blood, breaking of heart, weary in body, blind from his own blood that came from a crown of thorns. And Jesus said "I can't make it any further." Yet He climbed on up to Calvary and stretched out his arms as he hung on the cross, and said, "Father, forgive them; for they know not what they do." He went on when He couldn't go on. He finished it when He couldn't, but He did.
Salvation is worth working for. It is worth a man's going round the world on his hands and knees, climbing its mountains, crossing its valleys, swimming its rivers, going through all manner of hardship in order to attain it. But we do not get it in that way. It is to him who believes.
A man is not saved against his will, but he is made willing by the operation of the Holy Ghost. A mighty grace which he does not wish to resist enters into the man, disarms him, makes a new creature of him, and he is saved.
From the Word of God I gather that damnation is all of man, from top to bottom, and salvation is all of grace, from first to last. He that perishes chooses to perish; but he that is saved is saved because God has chosen to save him.
Genuine faith that saves the soul has for its main element - trust - absolute rest of the whole soul - on the Lord Jesus Christ to save me, whether He died in particular or in special to save me or not, and relying, as I am, wholly and alone on Him, I am saved.