Hebrew tsebaot (not Sabbath, an altogether different word), i.e. "of hosts", namely, of the heavenly powers (1Ki_22:19; Psa_103:21; Psa_148:2; Rom_9:29; Jas_5:4, reminding the rich who think the poor have no advocate that the Lord of the whole hosts in heaven is their patron). Implying the boundless resources at His command for His people's good (Psa_59:5). The sabaoth included both the angelic and starry hosts. The latter were objects of the idolatry, hence called sabaism (2Ki_17:16). God is above even them (1Ch_16:26). The "groves" symbolized these starry hosts. In contrast, Jehovah is the Lord of them, therefore alone to be worshipped. The title does not occur in the Pentateuch, nor earlier than 1Sa_1:3, but in the singular Jos_5:14-15.
Fausset's Bible Dictionary
By Andrew Robert Fausset, co-Author of Jamieson, Fausset and Brown's 1888.