τηρέω, -ῶ
[in LXX for שָׁמַר, נָצַר, etc.;]
1. to watch over, guard, keep, preserve: Mt 27:36, Ac 16:23, al.; ἑαυτόν, II Co 11:9, I Ti 5:22, Ja 1:27, Ju 21; seq. εἰς, Jo 12:7, Ac 25:21, I Pe 1:4, II Pe 2:4, 93:7, Ju 6; ἐν, Jo 17:11, 12, Ju 21; ἐκ, Jo 17:15, Re 3:10; τ. πίστιν, II Ti 4:7, Re 14:12; τ. ἑνότητα τ. πνεύματος, Eph 4:3.
2. to watch, give heed to, observe: τ. σάββατον, Jo 9:16; τ. ἐντολήν (-άς), Mt 19:17, Jo 14:1515:10, I Ti 6:14, I Jo 2:3, 43:22, 245:3, Re 12:1714:12; τ. λόγον (-ους), Jo 8:51, 52, 5514:23, 2415:2017:6, I Jo 2:5, Re 3:8, 1022:7, 9; τ. νόμον, Ac 15:5, Ja 2:10; τ. παράδοσιν, Mk 7:9; τ. ἔργα, Re 2:26; τ. γεγραμμένα, Re 1:3 (cf. δια-, παρα-, συν-τηρέω)
SYN.: φυλάσσω, implying custody and protection: τ. expresses the idea of watchful care and "may mark the result of which φ. is the means" (Thayer s.v.).