en_tn/php/01/27.md

that you are standing firm in one spirit, with one mind striving together for the faith of the gospel

The phrases "standing firm in one spirit" and "with one mind striving together" share similar meanings and emphasize the importance of unity. (See: rc://en/ta/man/translate/figs-parallelism)

with one mind striving together

"striving together with one mind." Agreeing with one another is spoken of as having one mind. AT: "agreeing with one another and striving together" (See: rc://en/ta/man/translate/figs-metaphor)

striving together

"working hard together"

for the faith of the gospel

Possible meanings are 1) "to spread the faith that is based on the gospel" or 2) "to believe and live as the gospel teaches us"