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.
The Lord JEHOVAH - Hebrew, Yah, Yahweh. The repetition of the name denotes emphasis, and the unchangeableness of God's character.
(Is) my strength and my song; he also is become my salvation - derived from Exodus 15:2; Psalms 118:14. The idea of salvation was peculiarly associated with the Feast of Tabernacles (see Isaiah 12:3). Hence, the cry "Hosanna," Save, we beseech thee, that accompanied Jesus' triumphal entry into Jerusalem (Matthew 21:9: cf. with Psalms 118:25-26): the earnest of the perfected "salvation" which He shall bring to His people at His glorious second appearance at Jerusalem (Hebrews 9:28, "He shall appear the second time without sin unto salvation"). Compare Revelation 21:3, "the tabernacle of God is with men:" cf. Luke 9:33, "three tabernacles: one for thee," etc. (the transfiguration being a pledge of the future kingdom) (Psalms 118:15, "The voice of rejoicing and salvation is in the tabernacles of the righteous;" Zechariah 14:16, "everyone that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the Lord of hosts, and to keep the feast of tabernacles").
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" (Psalms 107:7). As branches of palms were taken on the first day of the feast with rejoicing, so shall the "multitude which no man can number, stand before the throne, and before the Lamb," with "palms in their hands" (Revelation 7:9). Since the Passover feast has its Christian antitype in Easter, the commemoration of Christ's resurrection, which succeeds the day of commemoration of the sacrifice of Christ's death; and Pentecost has its antitype in Whitsunday, the feast commemorating the gift of the Holy Spirit, so the Feast of Tabernacles, the third great feast, shall have its antitype in the Millennial reign of Christ and His saints over Israel, settled again in her fatherland, and over the nations, when the harvest-home of the elect Church shall be complete, and Israel shall keep her harvest-home feast in her own land, after her long wilderness-like wanderings.