Abraham had only one son.
By faith Abraham when he was tried, offered up Isaac, , his only begotten son.
Take now thy son, thine only son Isaac, , and offer him there for a burnt offering.
Abraham had more than one son.
And Hagar bare Abraham a son: and Abram called his son's name, which Hagar bare, Ishmael.
For Sarah conceived, and bare Abraham a son is his old age , And Abraham called him Isaac.
Then again Abraham took a wife, and her name was Keturah. And she bare him Zimran, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah.
Abraham had two sons; the one by a bond-woman, and the other by a free woman.