Two of God’s names are stated in verse three, “Know that the Lord, He is God.” Another way of saying verse three is know that the LORD (Yehovah or I AM) is God (Elohim or faithful.
God is faithful to fulfill His promise to Abraham by providing a seed, “Look now toward heaven, and count the stars if you are able to number them.” And He said to him, “So shall your descendants be” Genesis 15:5. One way the faithfulness of God can be measured is by the offspring He provided to Abraham.
We are told to praise God for His goodness and mercy, “Be thankful to Him, and bless His name. For the Lord is good; His mercy is everlasting…” Psalm 100:4-5. Gratitude for the Christian begins with the truth that we are, “…His people and the sheep of His pasture” Psalm 100:3.
Why we are His people is stated in Romans 9:8, “That is, those who are the children of the flesh, these are not the children of God; but the children of the promise are counted as the seed.” God promised a seed to Abraham and it is the promise and not the gene pool that determines who the seed is. “For this is the word of promise“: At this time I will come and Sarah shall have a son” Romans 9:9 (Emphasis added). God opens the womb because he is the author of life; it is also true in salvation, that man has no part in the fulfillment of God’s promise. Sinful men always seek to distort the simple and sublime reality that God fulfills His own promises; faithfulness is part of God’s divine character and it is revealed in His name and Word.
The Christian can, say with the Psalmist, “For the Lord is good; His mercy is everlasting” Psalm 100:5, because he knows that it is God keeping his own promise and saving a people whom He chooses, which makes God sovereign, merciful, and full of grace. God is not compelled to choose anyone, if He were He would not be God, and salvation would not be by grace, and grace by definition is without obligation.
“I will have mercy on whomever I will have mercy, and I will have compassion on whomever I will have compassion” Romans 9:15.