This is NOT true, a clear read of the account of Abraham’s servant and Rebecca depicts Rebecca as a young woman not a child. (Genesis 24:1-51) Sarah died when Isaac was in his late thirties. After her death, Abraham sent one of his servants to find a wife for Isaac from their clan, as Abraham was determined his son should not have a Canaanite for a wife (Genesis 24:1-51). Abraham’s servant prayed to have success in finding a suitable wife, and God directed his quest. When he was forty, Isaac married his cousin Rebekah (Genesis 25:20). The Bible tells us that "he loved her; and Isaac was comforted after his mother’s death" (Genesis 24:67).
At age sixty, Isaac became the father of twins—Jacob and Esau. While Isaac favored his elder son, Esau, Rebekah’s favorite was Jacob. This caused great rivalry within the family and led to Jacob, the younger son, receiving the inheritance and his father’s blessing that should have gone to Esau, the older son, after Isaac and Esau were deceived by Rebekah and Jacob. Isaac became aware of the deceit but could not revoke his blessing on Jacob (Genesis 27). Rebekah learned of Esau’s plan to kill Jacob after Isaac’s death and convinced Isaac to send Jacob to her brother Laban to find a wife among her relatives. Isaac again blessed Jacob before sending him on his way, praying that God would give Jacob the blessing given to Abraham.
Abraham died when Isaac was about seventy-five and left everything to him (Genesis 25:5). Though Ishmael had been sent away when Isaac was weaned, both Isaac and Ishmael buried Abraham (Genesis 25:9). The Bible does not talk specifically about their relationship, and the descendants of Ishmael and those of Isaac have historically been enemies; animosity remains to this day. But it is interesting to note that the two men apparently united in mourning their father.
When there was a famine in the land, God appeared to Isaac and told him not to go to Egypt but to remain in the land. God promised to be with Isaac and bless him and give the land to Isaac’s descendants. God reaffirmed the covenant He had made with Abraham, saying that He would make his descendants as numerous as the stars and bless all the nations of the earth through them (Genesis 26:1–6).
Isaac remained in the land of Canaan. But, similar to what his father had done years before his birth, in fear, Isaac presented Rebekah as his sister rather than his wife (Genesis 26:7–11). But, just as God had protected Sarah, He also protected Rebekah. God blessed Isaac with bountiful crops and wealth, so much so that the Philistines became jealous and stopped up the water wells Abraham had dug. The Philistine king asked Isaac to move, and Isaac complied, moving from place to place digging new wells when his enemies quarreled with him over the water. The Philistine king soon recognized that Isaac had been blessed by God and made a treaty of peace between them (Genesis 26:26–31).
Isaac died at the age of 180 and was buried by both his sons. God affirmed His covenant with Isaac’s son, Jacob, whom He renamed Israel.