en_tn/rev/14/04.md

have not defiled themselves with women

Possible meanings are 1) "have never had immoral sexual relations with a woman" or 2) "have never had sexual relations with a woman." Defiling oneself with women may be a symbol of worshiping idols.

they have kept themselves sexually pure

Possible meanings are 1) "they did not have sexual relations with a woman who was not their wife" or 2) "they are virgins."

follow the Lamb wherever he goes

Doing what the Lamb does is spoken of as following him. AT: "they do whatever the Lamb does" or "they obey the Lamb" (See: rc://en/ta/man/translate/figs-metaphor)

bought out of mankind as firstfruits

"Firstfruits" here is a metaphor for the first offering to be made to God in celebration of harvest. AT: "purchased out of the midst of the rest of mankind as a special celebration of salvation" (See: rc://en/ta/man/translate/figs-metaphor)