The Lord knows, out of all mankind who belongs to Him, and who does not. It is Him and Him alone that chooses those who are His children. Though from ages of old up until now His call has gone out to multitudes who refused to listen but turned their backs in rebellion to the Lord of Glory. Though His hand of love, mercy, and grace has been stretched out to them all this time. The message of redemption was given to them, but they continued in their rebellion.
But remember, you do not know who will receive the wonderful gift of repentance and fall before the Lord. Calling upon His name for forgiveness. There will be many who refuse to listen to you. Who will revile and accuse you of wrong? Acting hypocritically in their own wrongdoing. They will turn away from the soul-saving message of salvation through Jesus Christ.
The good news is, that some will listen. Some of those you least expect will cry out to the Lord for His mercy and grace. They will weep for their sins and repent. God will change them, and they will be saved from eternal death. You will be blessed in many ways at that time, and in the age to come great reward.
How exciting it is that you can take part in saving a soul from eternal destruction. Bringing the truth to a lost child of God. That God would choose you, not because of anything you have done, but what He has done. That you can be filled with great joy, knowing you have accomplished His will. His love, compassion, mercy, and grace have been poured out on His beloved child. And the angels in heaven will rejoice with great delight.
But it is not as though the word of God has failed. For not all who are descended from Israel belong to Israel, and not all are children of Abraham because they are His offspring, but “Through Isaac shall your offspring be named.” This means that it is not the children of the flesh who are the children of God, but the children of the promise are counted as offspring.
For this is what the promise said: “About this time next year I will return, and Sarah shall have a son.” And not only so, but also when Rebekah had conceived children by one man, our forefather Isaac, though they were not yet born and had done nothing either good or bad—in order that God’s purpose of election might continue, not because of works but because of Him who calls— she was told, “The older will serve the younger.” As it is written, “Jacob I loved, but Esau I hated.”
What shall we say then? Is there injustice on God’s part? By no means! For He says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” So then it depends not on human will or exertion, but on God, who has mercy. Romans 9:6-16