The Philistines fought Israel, killing Saul and Jonathan, but when David heard of it, he did not rejoice that the man, Saul, who had been trying to kill him, was dead, and David certainly would not have rejoiced in the death of his best friend. Truly, David began a song with these words about Saul and Jonathan,
“The beauty of Israel is slain on your high places!
How the mighty have fallen!
Tell it not in Gath,
Proclaim it not in the streets of Ashkelon—
Lest the daughters of the Philistines rejoice,
Lest the daughters of the uncircumcised triumph.”
(2 Samuel 1:19–20)
I hear people who do not like the ruler of their nation, or they do not care for a leader in the church, and they tell it to others freely, and rejoice when they fall, but we could all learn from David, who recognized that the fall of the king of Israel and one of his princes was a mark, not so much against those men, but against Israel.
Therefore, David did not want the Philistines to hear of the defeat of their enemy.