Concise Bible Dictionary:
We do not meet with this name until 1 Samuel 1:3. It came in with prophetic testimony, faith laying hold of Jehovah’s glory when Israel had corrupted themselves, and were in a weak and low estate. Scripture reveals that there is a mighty heavenly host, and principalities and powers in the unseen world. God is the God of them all, as well as God of all the elements of nature, which have often been used by Him to punish His enemies. “The stars in their courses fought against Sisera” (Judg. 5:20). We read of “the God of hosts” only a few times comparatively; it is mostly “Jehovah of hosts,” and at times “Jehovah God of hosts,” showing that it is in connection with Israel that God revealed Himself under this name. Jehovah of hosts dwelt between the cherubim. From the beginning of 1 Samuel these titles constantly occur to the end of the Old Testament In Psalm 24:10 the Lord Jesus is shown to be “Jehovah of hosts: He is the king of glory” (Compare Eph. 1:20-21; Col. 1:16). The same title occurs in the New Testament as the LORD OF SABAOTH (Rom. 9:29, in a quotation from Isa. 1:9, and James 5:4).