The language in verses 16-17 reflects Isa 49.10.

They shall hunger no more, neither thirst any more: this may be translated “Never again will they be hungry or thirsty” or “They will never be hungry again or ever be thirsty again.”

The sun shall not strike them: this means that the hot rays of the sun will not harm them (see Psa 121.6). The Greek word translated scorching heat may mean “the (desert) wind,” reflecting the meaning of Isa 49.10 (so New Jerusalem Bible). Or else sun and scorching heat may refer only to the sun’s heat: “the burning heat of the sun will not harm them” (so Translator’s New Testament).

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 .