The Lord says, “Come, everyone who is thirsty— here is water! Come, you that have no money— buy corn and eat! Come! Buy wine and milk— it will cost you nothing!” (Isaiah 55:1, GNB)

On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink.” (John 7:37, ESV)

Jesus was saturated with the Tanakh (the Old Testament) and here he claims for himself the words of Isaiah 55.1.  God offers water freely, it remains to Jesus in Jerusalem to work out that God is not offering physical water, but water that will last forever, or as he told the Samaritan woman:

Jesus said to her, “Everyone who drinks of this water will be thirsty again, but whoever drinks of the water that I will give him will never be thirsty again. The water that I will give him will become in him a spring of water welling up to eternal life.”” (John 4:13–14, ESV)

In Jesus, God calls those who are thirsty to drink freely of water from which they will never thirst again.