Exodus 17:15

Jehovah-nissi - Jehovah is my ensign or banner. The hands and rod of Moses were held up as soldiers are wont to hold up their standards in the time of battle; and as these standards bear the arms of the country, the soldiers are said to fight under that banner, i.e., under the direction and in the defense of that government. Thus the Israelites fought under the direction of God, and in the defense of his truth; and therefore the name of Jehovah became the armorial bearing of the whole congregation. By his direction they fought, and in his name and strength they conquered; each one feeling himself, not his own, but the Lord's soldier.

Jehovah-nissi - See the margin, "Jehovah my banner." As a proper name the Hebrew word is rightly preserved. The meaning is evidently that the name of Yahweh is the true banner under which victory is certain; so to speak, the motto or inscription on the banners of the host. Inscriptions on the royal standard were well known. Each of the Pharaohs on his accession adopted one in addition to his official name.

17:15 And Moses built an altar, and called it Jehovah - niffi - The Lord is my banner. The presence and power of Jehovah was the banner under which they were lifted, by which they were animated, and kept together, and therefore which they erected in the day of their triumph. In the name of our God we must always lift up our banners: He that doth all the work should have all the praise. Write this for a memorial - This is the first mention of writing we find in scripture; and perhaps the command was not given till after the writing of the law on tables of stone.