The LORD hath made known his salvation: his righteousness hath he openly shewed in the sight of the heathen.
The Lord hath made known his salvation ... all the ends of the earth have seen the salvation of our God - (Isaiah 52:10.) His righteousness (Psalms 97:6) - corresponding to His "truth" or faithfulness (Psalms 98:3; Romans 15:8-9). Salvation to His people is the effect of His righteousness (cf. Isaiah 45:17; Isaiah 45:24-25).
Verse 3. He hath remembered his mercy and his truth toward the house of Israel - (Isaiah 63:7.) So the Virgin's song, Luke 1:54-55; Luke 1:72.
The salvation of our God is first to be manifested to Israel, and through Israel to "all the ends of the earth".
All the ends of the earth. So it was in the case of the elect Church at Messiah's first coming (Luke 24:47). So it shall be in the case of the world-wide Church, of which Zion shall be the center, at His second coming (Isaiah 2:2-3).