Extended Strong's Greek Lexicon (Abbott-Smith based)
be at peace
Usage: εἰρηνεύω (εἰρήνη), [in LXX chiefly for שׁלם, שׁקט ;] __1. to bring to peace, reconcile (so 1Ma.6:60). __2. to keep peace, be at peace: Mrk.9:50, Rom.12:18, 2Co.13:11, 1Th.5:13 (cf. Sir.28:9; Cremer, 246). † (AS)