“I have blotted out, as a thick cloud, thy transgressions, and, as a cloud, thy sins: return unto Me; for I have redeemed thee.” Sing, O ye heavens; for the LORD hath done it: shout, ye lower parts of the earth: break forth into singing, ye mountains, O forest, and every tree therein: for the LORD hath redeemed Jacob, and glorified Himself in Israel. – Isaiah 44:2,23

In the fullness of time Jesus appeared, and up to the tree carried all the sins of His people. Having all His life long carried their sicknesses and sorrows, He bore the burden of sin to the place of its annihilation, and by His death He made an end of it. Apart from the atonement, the chosen of God, like other men, lay under sin; the black cloud was over all the race, but Jesus took the dense mass of all the transgressions of His people, past, present, and to come, and obliterated the whole, even as a cloud is blotted out from the face of heaven. Jesus took the whole incalculably ponderous load, all charged with tempest as it was, and bore it all upon those shoulders, which must have been crushed to the earth had they not been divine: on the tree He bore that sin and the wrath which was due to it, feeling all its crowded tempests in His own soul, until in that moment when He had borne all, and ended all, He sent up the victorious shout of “It is finished.” Then shone forth the unclouded glory of boundless love; then was gone for ever the threatened storm; then righteousness sprang out of the earth, and peace looked down from heaven, and the reconciled ones might well exclaim, “Sing, O heavens; for the Lord hath done it: shout, ye lower parts of the earth: break forth into singing, ye mountains, O forest, and every tree therein: for the Lord hath redeemed Jacob, and glorified Himself in Israel.” Sin was put away, transgression was cast into the depths of the sea, and loud o’er all rang out the jubilant challenge-“Who shall lay anything to the charge of God’s elect? who is he that condemneth, now that Christ hath died?” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1240.cfm

And last of all He was seen of me also, as of one born out of due time. For I am the least of the apostles, that am not meet to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am… – 1 Corinthians 15:8-10

How do we know that Paul was born again, and that he was called to be an apostle of Jesus Christ?

See how he confessed his sin and forsook it. He that covereth his sins shall not prosper; but whoso confesseth and forsaketh them shall have mercy.” Are you, dear friend; willing now to confess your sin? Do you turn from it with loathing. Do you desire, henceforth, to be delivered entirely from it? Well, then, your repentance is another sure evidence that you are born again. If you have seen Jesus taking your sin upon Himself and suffering its dread penalty; if you have confessed your sin, and by faith laid it upon Him as your Sacrifice and Substitute, you are born again, though you may have been, in a certain sense, “born out of due time.”

I am sure he was converted, also, because he praised the grace of God. Read the 10th verse: “By the grace of God I am what I am.” Even when he truthfully says, “I labored more abundantly than they all;” he humbly adds, “yet not I, but the grace of God which was with me.” It is a sure sign of conversion when a man knows that he is saved by grace alone, and does not, attribute it to his own merit, or his own work, but praises and adores the sovereign mercy and grace of God. Have you that evidence, dear friend? Then are you born aright, even though “born out of due time.” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2663.cfm

He that is our God is the God of salvation; and unto GOD the Lord belong the issues from death. – Psalm 68:20

And last of all He was seen of me also, as of one born out of due time. – 1 Corinthians 15:8

I should like to encourage any very aged person who is still unsaved to drive away altogether the notion that it is too late to seek the Lord. It never is too late so long as life lasts and there is the power to repent of sin and to turn to the Lord. I will not quote cases, but I have a vivid recollection of a good many persons who have been saved at the age of seventy or eighty. We have had persons, past both of those periods, baptized upon profession of their newly found faith. The world’s proverb says, “It is never too late to mend:” ‘but Christ would tell you, if He were here in bodily presence, that it is never too late for Him to mend you, or rather, for Him to make you anew, for that is the work He undertakes to do. It is never too late for Him to stretch out His pierced hand and help the man, who is tottering on his staff, to become a babe in Christ.

Many of you have not yet come of old age, yet, if God should save you, you would be as those who are “born out of due time,” because you are on the very brink of the grave. Consumption has laid its cruel hand upon you and pulled down all your strength. In all probability, you will not be long in this world…O my dear young friend, wherever you may be, it is a sad, sad thing to be carrying about with you your death-warrant, as you certainly are doing, and yet to have no warrant to believe that, when you die, it will be well with you! Oh, I pray you, do not let Satan tempt you with the idea that, now, when sickness is upon you, there is no hope for you! Come to Jesus, however consumptive you look. Come to Jesus, young man, with that chest that scarcely allows you to breathe. Come unto Him, for He will not cast you away. I beseech any of you, who are in a similar condition, do not put off seeking the Lord, but hasten to find Him even now. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2663.cfm