ἀλλὰ διὰ τῆς ἀγάπης δουλεύετε ἀλλήλοις. ὁ γὰρ πᾶς νόμος ἐν ἑνὶ λόγῳ πεπλήρωται, ἐν τῷ Ἀγαπήσεις τὸν πλησίον σου ὡς σεαυτόν → but be enslaved to each other through love; for the whole Torah is fulfilled in one statement: You will love your neighbor as yourself (Galatians 5:13f.)
zealous: P. and V. πρόθυμος, ἔντονος, σύντονος.
be on the alert: P. διὰ φυλακῆς ἔχειν, V. ἐν εὐφυλάκτῳ εἶναι; see watch.