“Jesus answered and said to her, “Everyone who drinks of this water will thirst again; but whoever drinks of the water that I will give him shall never thirst; but the water that I will give him will become in him a well of water springing up to eternal life.””
‭‭John‬ ‭4‬:‭13‬-‭14‬ ‭NASB1995‬‬
https://bible.com/bible/100/jhn.4.13-14.NASB1995

Comments on this Verse

4:10 living water. The OT is the background for this term, which has important metaphorical significance. In Jer 2:13, Yahweh decries the disobedient Jews for rejecting Him, the “fountain of living waters.” The OT prophets looked forward to a time when “living waters will flow out of Jerusalem” (Eze 47:9; Zec 14:8). The OT metaphor spoke of the knowledge of God and His grace which provides cleansing, spiritual life, and the transforming power of the Holy Spirit (cf. Is 1:16–18; 12:3; 44:3; Eze 36:25–27). John applies these themes to Jesus Christ as the living water which is symbolic of eternal life mediated by the Holy Spirit from Him (cf. v. 14; 6:35; 7:37–39). Jesus used the woman’s need for physical water to sustain life in this arid region in order to serve as an object lesson for her need for spiritual transformation. † 4:15 The woman, like Nicodemus (3:4), did not realize that Jesus was talking about her spiritual needs. Instead, in her mind, she wanted such water in order to avoid her frequent trips to Jacob’s well.

John MacArthur Study Bible