Jamieson, Fausset and Brown on 1 Samuel 7:3-6

3-6. Samuel spake unto all the house of Israel--A great national reformation was effected through the influence of Samuel. Disgusted with their foreign servitude, and panting for the restoration of liberty and independence, they were open to salutary impressions; and convinced of their errors, they renounced idolatry. The re-establishment of the faith of their fathers was inaugurated at a great public meeting, held at Mizpeh in Judah, and hallowed by the observance of impressive religious solemnities. The drawing water, and pouring it out before the Lord, seems to have been a symbolical act by which, in the people's name, Samuel testified their sense of national corruption, their need of that moral purification of which water is the emblem, and their sincere desire to pour out their hearts in repentance before God.