1 Samuel 15:4

And Saul gathered the people together, and numbered them in Telaim, two hundred thousand footmen, and ten thousand men of Judah.

Saul gathered the people together and numbered them at Telaim before attacking the Amalekites, counting two hundred thousand foot soldiers and ten thousand men of Judah. That campaign carried out God's sentence against the Amalekites for attacking Israel in the wilderness, a sentence delayed for four hundred years until the time for its execution had come. It was a work of justice that God commanded Saul to carry out fully. Saul failed to carry it out fully, following his own judgment by sparing Agag and the best of the livestock. His failure to destroy Amalek brought God's wrath upon him.