I'm confused.
Ishmael was Abraham's son by a concubine; Isaac was his son by his wife Sarah. KEY POINT: God's covenant was made with Abraham and extended through Isaac, not Ishmael.
MM
Ishmael was the illegitimate son of Abraham that he had when Sarah believe she was barren and convinced Abraham to have relations with her maid, Haggar.
God promised Abraham he would be the father of many nations, and he promised him a son, even though he and Sarah were very very old and childless.
In their unbelief, Sarah and Abraham decided to help God out with His promise, and Abraham slept with Sarah’s servant, Hagar. Hagar bore a son they named Ishmael.
Sarah became pregnant and bore a son they named Isaac.
At this point, the Jewish and Christian teachings differ from the Islamic teachings. The Judeo-Christian scriptures teach that Abraham recognized his sin (lack of faith in God’s promise) and in obedience to ancient prophecies drove out Hagar and Ishmael.
Years later, God instructed Abraham to take his only son, Isaac, and to sacrifice him on an altar. Abraham obeyed, and the Angel of the Lord stopped him at the last second and offered a substitution for the sacrifice: a ram.
The Muslims on the other hand, believe that Ishmael was the true son of Abraham, and that he was the one on the altar.
The Jews are the descendants of Abraham and Isaac. The Arabs are the descendants of Abraham and Ishmael. Throughout the bible, these two nations have warred.