Оу҆цѣломꙋдритесѧ и҆ трезвитесѧ въ мл҃твахъ. Пре́жде же всѣ́хъ дрꙋ́гъ ко дрꙋ́гꙋ любо́вь прилѣ́жнꙋ и҆мѣ́йте, занѐ любовь
This bolded portion from 1 Peter 4:7-8:
"For the end of all things is at hand; therefore, be vigilant and sober in [your] prayers. Before all, to one another have fervent love, for love covers a multitude of sins."
(I've provided my own translation for the relevant bit but I suggest glancing at whichever you prefer. The word being translated as "be vigilant" is generally taken to mean "be chaste" but looking at its roots, it has the more general meaning of being fully mindful.)