1 Samuel 11:7
And he took a yoke of oxen, and hewed them in pieces, and sent them throughout all the coasts of Israel by the hands of messengers, saying, Whosoever cometh not forth after Saul and after Samuel, so shall it be done unto his oxen. And the fear of the LORD fell on the people, and they came out with one consent.
And if ye go to war in your land against the enemy that oppresseth you, then ye shall blow an alarm with the trumpets; and ye shall be remembered before the LORD your God, and ye shall be saved from your enemies.
And it came to pass, when he was come, that he blew a trumpet in the mountain of Ephraim, and the children of Israel went down with him from the mount, and he before them.
But the Spirit of the LORD came upon Gideon, and he blew a trumpet; and Abiezer was gathered after him.
1 Samuel 13:3-4
And Jonathan smote the garrison of the Philistines that was in Geba, and the Philistines heard of it. And Saul blew the trumpet throughout all the land, saying, Let the Hebrews hear. And all Israel heard say that Saul had smitten a garrison of the Philistines, and that Israel also was had in abomination with the Philistines. And the people were called together after Saul to Gilgal.