In the last day, that great day of the feast, Jesus stood and cried, saying, If any man thirst, let him come unto me, and drink.
John 7:37
It was the Fall feasts and the whole nation of Israel was gathered at Jerusalem. Having observed the Feast of Trumpets and Atonement in the last two weeks, the Fall feasts was drawing to a close with the Feast of Tabernacles. On the last day, the Levites were at the Pool of Siloam -- the only pool in the city with living waters. They drew the water into a golden goblet and brought it up to the temple, pouring it into one of the two silver basins adjoining the altar; and in the other basin, they poured wine. As the procession went on, the Jews were chanting from Isa 12, a commeoration of water being drawn from the rock as the nation of Israel wandered through the desert.
And as they chanted "with joy shall you draw water out of the wells of salvation" (Isa 12:3), Jesus stood up in the midst of the people, and cried, saying "If any man thirst, let him come unto me, and drink".
And as they chanted "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" (Isa 12:2), little did they know, the one standing in their midst was truly their salvation incarnate! And the Jews chanted "Cry out and shout, thou inhabitant of Zion: for great is the Holy One of Israel in the midst of thee" (Isa 12:6) -- and it was true - the Holy One of Israel was right there in Zion, in their midst!
As the choir sang the hallel from Psalm 118, they would have come across "the LORD is my strength and song, and is become my salvation" (v14), "I will praise you, for you have heard me, and are become my salvation" (v21), and yet when their salvation stood in their midst, and they did not recognize the significance of that moment.
The one whom they have been longing for and singing about was standing in their midst, and they did not see! Moses wrote "the LORD is my strength and song, and is become my salvation" (Ex 15:2). The Law (Torah), the Prophets, and the Psalms all proclaimed God's salvation, and year after year, God had the nation of Israel to rehearse the feasts, so they would remember His promises and at the coming of His anointed, they would truly sing and shout.
Pray for the nation of Israel. That they may receive the Spirit of God and thirst no more.