"Then Abraham planted a tamarisk tree in Beersheba, and there called on the name of the LORD, the Everlasting God, El Olam."
Genesis 21:33
The covenant God made with Abraham is everlasting.
"I will establish My covenant between Me and you and your descendants after you in their generations, for an everlasting [olam] covenant, to be God to you and your descendants after you"
Genesis 17:7.
Those who believe in the Lord Jesus Christ are called descendants of Abraham. "And if you are Christ's, then you are Abraham's seed, and heirs according to the promise"
Galatians 3:29
In Christ, we are heirs to an everlasting covenant with an everlasting God.
"The LORD is good; His mercy is everlasting [olam]"
Psalm 100:5.
God's mercy in Hebrew is His covenant love and faithfulness.
He has committed Himself to our well-being, and He will not break His promise.
Not ever!