Abraham had a total of eight sons according to the Bible:

• His first son was Ishmael, born to Hagar, Sarah’s Egyptian maidservant (Genesis 16:1–4).
• His second son was Isaac, born to his wife Sarah, the son of promise through whom God’s covenant was established (Genesis 21:1–3).
• After Sarah’s death, Abraham married Keturah, who bore him six sons: Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah (Genesis 25:1, 6).

While Abraham had eight biological sons, Isaac is often referred to as his "only son" in the context of God's covenant and promise, as he was the sole heir through Sarah and the line through which the covenant was fulfilled. Ishmael and the six sons of Keturah were not part of this covenant inheritance but became heads of other tribes and nations (Genesis 22:2; Hebrews 11:17; Galatians 4:22). Thus, Abraham’s biological sons numbered eight, but Isaac is distinguished as the son of promise and covenant heir