It is done!: see 16.17. In Greek the verb here is plural, “They are done,” as contrasted with the singular in 16.17. The antecedent is probably “these words,” and the translation can be “All these things are now done (or, accomplished),” “I have done all these things,” or “I have caused all these things to happen.”

I am the Alpha and the Omega, the beginning and the end: see 1.8; 1.17; 22.13. The two declarations mean the same: “I am the first and the last; I am the beginning and the end.” In this context perhaps “I begin all things and bring all things to an end” will be more natural in many languages.

To the thirsty I will give: it may be better to follow the normal order, “I will give to anyone who is thirsty” or “I will give to all who are thirsty,” or in certain languages, “I will give to anyone who craves water.”

From the fountain of the water of life: “I will give the water that comes from the fountain of life-giving water” or “I will give them water to drink from a place where water is flowing that gives life.” See similar language in 7.17; 22.17.

Without payment: it should be clear that it is the one who drinks the water who will not have to pay. “I will give them, free of charge, water” (see 7.17). The last sentence in this verse may be translated as follows: “I will give to all who are thirsty water to drink from the fountain of life-giving water, and they will not have to pay for it” or “I will give water to all who are thirsty. This water comes from a place where water is flowing that gives life. They do not have to give anything in return.”

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .