A contrast is evident between the tense of the verb drinks in this verse and in the preceding verse. The verb in verse 13 is in the present tense, suggesting habitual action; in verse 14 the word drinks is in the aorist tense, suggesting a single action. Thus the water from Jacob’s well supplies only the physical needs of men, and only temporarily, so that people must return for more. One drink of the water that Jesus gives for the spiritual needs of people provides eternal life. The contrast between the present and aorist forms of the verb drink may be indicated in some languages by translating the first part of verse 14 “If anyone ever drinks the water that I give him, he will never be thirsty again” or “But if he once drinks the water….”
Will never be thirsty again (so Jerusalem Bible; Moffatt “will never thirst any more”; see New English Bible, Goodspeed) is literally “will not be thirsty into the age.” In this context “the age” (see comments at 3.15) is equivalent to “eternity” or “forever,” and when joined with a negative (“not … into the age”), the meaning is never … again.
In the Greek the next sentence reads literally “but the water which I will give to him will become in him a spring of water leaping up into eternal life.” To make explicit the meaning of “spring of water leaping into eternal life,” Good News Translation has a spring which will provide him with life-giving water and give him eternal life, which is clearly the meaning. Most translations are rather formal in their rendering. New American Bible attempts to make a dynamic equivalent by translating “the water I give shall become a fountain within him, leaping up to provide eternal life.” In certain languages will become in him a spring may require some indication that this statement of Jesus is to be understood figuratively, for example, “will become in him just like a spring” or “will be in him something resembling a spring.”
The verb “leaping up” (see Acts 3.8, where TEV translates “jumped up … jumping” in its double occurrence) denotes lively action. In the Septuagint it is used of the coming of God’s “spirit” on Samson, Saul, and David, and some commentators believe it to be the background of its use in the present passage.
If life-giving water is translated “water that gives life,” it may be important to unite this expression with the phrase give him eternal life, that is, one may translate “provide him with water which gives him eternal life” or, in some languages, “… real life which never ends”—to emphasize the qualitative significance of eternal life, rather than merely its duration.
Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .