isaiah 12:2 Behold, God is my salvation; I will trust, and not be afraid: for the LORD JEHOVAH is my strength and my song; he also is become my salvation. - Free Bible Online

      2. Lord JEHOVAH--Jah, Jehovah. The repetition of the name denotes emphasis, and the unchangeableness of God's character.
      strength . . . song . . . salvation--derived from Ex 15:2; Ps 118:14. The idea of salvation was peculiarly associated with the feast of tabernacles (see Isa 12:3). Hence the cry "Hosanna," "Save, we beseech thee," that accompanied Jesus' triumphal entry into Jerusalem on that day (the fifteenth of the seventh month) (Mt 21:9; compare with Ps 118:25, 26); the earnest of the perfected "salvation" which He shall bring to His people at His glorious second appearance at Jerusalem (Heb 9:28). "He shall appear the second time without sin unto salvation." Compare Re 21:3, "The tabernacle of God is with men." Compare Lu 9:33, "three tabernacles: one for thee," &c. (the transfiguration being a pledge of the future kingdom), (Ps 118:15; Zec 14:16). As the Jew was reminded by the feast of tabernacles of his wanderings in tents in the wilderness, so the Jew-Gentile Church to come shall call to mind, with thanksgiving, the various past ways whereby God has at last brought them to the heavenly "city of habitation" (Ps 107:7).

JFB.