Who Was the Child of Promise, Isaac or Ishmael?

Muslims believe that they descended from Ishmael, the son born to Abraham's concubine. But as the Bible says many times, Isaac was the promised heir. Quite naturally, Muslims think they're right and that our scriptures were tampered with. I'll address that topic another time but for now, I need to show how Isaac was the one promised to Abraham.

Now it is true that Ishmael was born first but he wasn't the child God promised to give Sarah. We can see that in Genesis 16:3 (KJV) where it says, "And Sarai Abram's wife took Hagar her maid the Egyptian, after Abram had dwelt ten years in the land of Canaan, and gave her to her husband Abram to be his wife."

But we see who the child of promise was in Genesis 17:19 (KJV), "And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him."

Since the word "seed" is singular, we know it means Christ. He was promised from the beginning to be the saviour of humanity. As Galatians 4:28 (KJV) explains, "Now we, brethren, as Isaac was, are the children of promise." All who belong to Christ are counted as children of promise.

We also can tell that Ishmael had a different temperament than Isaac. Genesis 16:12 (KJV) describes him this way. "And he will be a wild man; his hand will be against every man, and every man's hand against him; and he shall dwell in the presence of all his brethren."

We who believe in Christ need to know the truth but we also must reject error. That's why I'm writing my book You Think You're Going to Heaven? Just as bank tellers can recognize a counterfeit bill, so we need to be so familiar with the truth that any lie will become blatant and obvious to us.