He stayed seven days, according to the set time that Samuel [had appointed]: but Samuel didn't come to Gilgal; and the people were scattered from him.
Israel’s regular army consisted of two divisions, one under the command of Saul, the other under the command of Saul’s son Jonathan. Other fighting men were called to join the army when needed. Such a need arose when Jonathan attacked a Philistine camp, and the Philistines replied by sending a large army to attack Israel (13:1-6a).In a time of national emergency, Saul was apparently to go to Gilgal, where he was to wait seven days for Samuel to arrive. By that time, Israel’s leaders would have gathered the army together. Samuel could then offer sacrifices to God on behalf of the nation, and pass on God’s instructions to Saul (see 10:8). The current Philistine attack tested Saul’s obedience. But rather than wait for Samuel, he offered the sacrifice himself. Probably his action resulted partly from impatience and partly from the desire to have complete power, religious as well as political (6b-9). Samuel saw that Saul’s action was really a rebellion against the authority of God. As punishment God would one day take the kingship from him and from his family (10-14).