David takes Goliath’s head
After David defeated Goliath, Saul asked him whose son he was. David put Goliath’s armor in his tent and took Goliath’s head to Jerusalem.
Key passages
1 Sa 17:54

And David took the head of the Philistine and brought it to Jerusalem and placed his weapons in his tent.

1 Sa 17:57–58

So when David returned from striking down the Philistine, Abner took him and brought him before Saul. The head of the Philistine was in his hand. Then Saul said to him, “Whose son are you, young man?” And David said, “I am the son of your servant Jesse the Bethlehemite.”

See also
Important Things