8. now—as the case is; seeing ye stand fast.
we live—we flourish. It revives us in our affliction to hear of your steadfastness (Ps 22:26; 2Jo 3:4).
if—implying that the vivid joy which the missionaries "now" feel, will continue if the Thessalonians continue steadfast. They still needed exhortation, 1Th 3:10; therefore he subjoins the conditional clause, "if ye," &c. (Php 4:1).