These two phrases mean basically the same thing and emphasize God's eternal nature. (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-merism]]).
These are first and last letters of the Greek alphabet. Possible meanings are 1) "the one who began all things and who ends all things" or 2) "the one who has always lived and who always will live." If unclear to readers you may consider using the first and last letters of your alphabet. AT: "the A and the Z" or "the first and the last." See how you translated this in [Revelation 1:8](../01/07.md). (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-merism]])
Possible meanings are 1) "the one who began all things and the one who will cause all things to end" or 2) "the one who existed before all things and who will exist after all things."
God speaks of a person's desire for eternal life as if it were thirst and of that person receiving eternal life as if he were drinking life-giving water. (See: [[rc://en/ta/man/translate/figs-metaphor]])