The Bible doesn’t say how old David was when he defeated Goliath. However, other biblical passages suggest he was a “Teenager.” Below, the definition of “Youth” is expanded upon, and David’s size is taken into account in order to make an educated guess as to David’s age at the time of his victory over Goliath.
David’s shape. David may very possibly have grown to a comparable amazing stature as his physically impressive brother Eliab because they shared the same parents (or at least the same father).
David Was A Teenager When He Killed Goliath!
1 Samuel 17:55-56 – “And when Saul saw David go forth against the Philistine, he said unto Abner, the captain of the host, Abner, whose son is this youth? And Abner said, As thy soul liveth, O king, I cannot tell. And the king said Enquire thou whose son the stripling is.”
Saul and Abner, Saul’s right-hand man (who would have examined David’s background for Saul’s protection), would have known who David was if he had been playing the harp for Saul the entire time. This explains why he was later referred to as a youth and then a mighty man of war.
The author chose not to tell the story chronologically so that he or she could contrast how the Holy Spirit came upon David after being anointed with Saul after Saul’s departure (1 Sam 16). Saul defied God, and the Spirit left him. David was anointed, and the Holy Spirit descended upon him.
1 Samuel 17:33 – “And Saul said to David, Thou art not able to go against this Philistine to fight with him: for thou art but a youth, and he a man of war from his youth.
Ishmael was forced to leave Abraham when he was between the ages of 16 and 19 and was given the same word for youth, H5288. Ishmael was born when Abraham was 86 years old (Gen. 16:16), Isaac was born when he was 100 years old (Gen. 21:5), and Ishmael was forced to leave after Isaac was weaned (Gen. 21:8), which was roughly two years after he was born (Gen 21:14).
Ishmael would then be at least 16 years old. David and I were about the same age. Ishmael and David were probably too young to be able to grow beards.