John Gill Commentary 1 Samuel 11:6

"And the Spirit of God came mightily upon Saul when he heard those words, and his anger was kindled greatly." — 1 Samuel 11:6 (ASV)

And the Spirit of God came upon Saul when he heard those
tidings
And filled him with pity and compassion to the inhabitants of Jabesh, and with wisdom and prudence, and set his thoughts at work to contrive ways and means for their relief, and with fortitude, courage, and resolution, to attempt their deliverance; so the Targum, ``the spirit of fortitude from the Lord dwelt on Saul:'' and his anger was kindled greatly; against Nahash the Ammonite for insulting Israel, and threatening to use the inhabitants of Jabesh in such a cruel manner.