God's mercies need memorial, and obtain it in several ways.
Deliverance from Amalek was a great and noticeable mercy. It was.
1. UNDESERVED, as the people had just been murmuring against God, and threatening to stone his prophet (Exodus 17:3-4).
2. TIMELY. Defeat, or even an indecisive success, would have brought upon the Israelites a host of enemies, under whose combined or continuous attacks they must have succumbed. The complete discomfiture of the powerful Amalek struck terror into the hearts of the neighbouring peoples, and induced them to leave Israel for nearly forty years unmolested.
3. WONDERFUL. Amalek was warlike, accustomed to contend with the great nation of the Egyptians; Israel had had all warlike aspirations checked and kept down by above 400 years of servitude and peace. Amalek was no doubt well armed; Israel can have possessed few weapons. Amalek knew the country, could seize the passes, and select a fitting moment for attack; to all Israel, except Moses and Aaron (Exodus 4:27), the country was strange, the passes unknown, and perhaps the very idea of their being attacked unforeseen and unexpected. The attack actually came close upon the great suffering from thirst, when Israel was "feeble" and "faint and weary" (Deuteronomy 25:18). So signal a mercy deserved special remembrance. Men soon forget the favours they receive at God's hands. That this favour might not be forgotten, God required two things:
1. That a record of it should be inserted in his book. There is no other memorial comparable with this, whether we consider the honour of it, since to obtain record there, an event must be indeed an important one; or the enduringness, since God's book will continue to the world's end; or the celebrity, since it is read by all nations. And God's special command for the insertion, stamps the event with an extra mark of dignity,
2. That it should be handed on traditionally to Joshua, and through him to others. Tradition is one of the modes by which God maintains the knowledge of his truth in the world, and is at no time wholly superseded by the written Word, since there are at all times persons in the world too young or too illiterate to have direct access to the Word, who must receive their religious instruction orally from teachers. Tradition alone would be a very unsafe guide; but tradition, checked by a book, is of no little value in enlarging the sphere of religious knowledge, and amplifying and rendering more intelligible the written record. To the two modes of securing continued remembrance of the defeat of Amalek required by God, Moses added a third—the erection of a material monument, to which he gave a commemorative name. Many victories have been thus commemorated, as those of Marathon, Blenheim, Trafalgar, Waterloo, etc.; but no erector of such a memorial has ever given to his work so noble and heart-stirring a name as Moses gave. "The Lord is my banner"—under no other standard will I serve or fight—no other leader will I acknowledge no other lord shall have dominion over me. "The Lord is my banner"—under this banner I engaged Amalek—he, and he alone, gave me the victory—through him, and him alone, do I look to discomfit my other enemies. Be the enemies material or spiritual, external or internal, to him only do I trust to sustain me against them. None other name is there under heaven, through whom salvation is to be obtained, the adversary baffled, Amalek put to confusion.