If we endure to the end we show we are saved.
Once God has forgiven our sins, He remembers them no more. (Hebrews 10.)
"Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works, Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered. Blessed is the man to whom the Lord will not impute sin." -- Romans 4:6-8 "I write unto you, little children, because your sins are forgiven you for his name's sake." -- 1 John 2:12
Our sins are not forgiven because we stop sinning. We sin every day. Our sins are forgiven because Christ has paid for every one of them and God remembers them no more.
So therefore Christians should not think they are spending their time trying to earn heaven, but instead they "work to show themselves approved." They work to illustrate the miracle of God's grace already within them. The good fruit comes from God who made men to differ.
AMEN
“And ye shall be hated of all men for my name's sake: but he that ENDURETH TO THE END SHALL BE SAVED” (emphasis mine).
It really has nothing to do with earning but with faithfulness, as Paul said at Heb. 10:38,39 even the righteous must be constant in their faith and not shrink back or they would lose God's favor to their destruction.
Again salvation was conditioned upon their continued endurance and not “shrinking back” in unfaithfulness.