Here the word "thirsty" is a metaphor that means one's great desire for the things of God, just as one "thirsts" for water. AT: "Those who desire the things of God like a thirty man desires water" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The word "drink" is a metaphor that means to receive the spiritual life that Jesus provides. AT: "let him come to me and quench his spiritual thirst" (See: [[rc://en/ta/man/translate/figs-metaphor]])