1 Samuel 14:35

And Saul built an altar unto the LORD: the same was the first altar that he built unto the LORD.

The altar Saul built belongs to a crisis that was permitted in order to rebuke his perversity and to teach the people humility and faith. That crisis followed his sin in making a presumptuous offering, and because of that sin he would not be given the honor of vanquishing the Philistines. Instead, the king's own son Jonathan, who feared the Lord, was chosen as the instrument to deliver Israel.

Moved by a divine impulse, Jonathan trusted that there is no restraint to the Lord to save by many or by few, and on that faith proposed a secret attack upon the enemy camp. His armor-bearer was also a man of faith and prayer, fully united with him in purpose. Together they withdrew secretly from the camp and sought the Guide of their fathers in earnest prayer. They agreed upon a sign to determine how they should proceed, and then made their way into the Philistine position.