Lexical Definition

‎βεβαιόω‎ bebaióō (beb-ah-yo'-o) to confirm G:V
from ‎βέβαιος‎

confirm, (e-)stablish.

Usage: 9 forms in 10 verses
Form Translated As     In Verse(s)
ἐβεβαιώθη it was confirmed Heb.2.3
was confirmed 1Cor.1.6
εβεβαίωσάσ firmed me up LXX.Ps.41.12
βεβαιῶσαι to confirm Rom.15.8
βεβαιῶν establishing 2Cor.1.21
βεβαιώσει will sustain 1Cor.1.8
βεβαιοῦσθαι to be strengthened Heb.13.9
βεβαιοῦντοσ confirming Mark.16.20
βεβαιούμενοι being strengthened in Col.2.7
βεβαίωσόν Firm LXX.Ps.119.28

Abbott-Smith

βεβαιόω, -ῶ (< βέβαιος), [in LXX: Ps 40 (41):12* (נצב hi.), 118 (119):28 (קוּם pi.), III Mac 5:42*;]
to confirm, establish, secure, of things (cl.): λόγον, [20](/btb/interlinear/41%20-%20Mark/16/Mark.16.20.html)]; ἐπαγγελίας, Ro 15:8; of persons (DCG, ii, 605): I Co 1:8, II Co 1:21. Pass., I Co 1:6, Col 2:7, He 2:3 13:9 (as an Attic legal term, to guarantee the validity of a purchase, establish or confirm a title; v. next word, Cremer, 139; cf. δια-β.).†

Abbott-Smith References

Book Refs
Psalms 41:12* · 119:28
Mark 16:20
Romans 15:8
1 Corinthians 1:6 · 1:8
2 Corinthians 1:21
Colossians 2:7
Hebrews 2:3 · 13:9

Liddell-Scott-Jones

βεβαιόω-όω,

confirm, establish, make good, τοῖς δικασταῖς τὴν δόξαν [Refs 5th c.BC+]; ἔργῳ βεβαιόωούμενα, opposed to ἀκοῇ λεγόμενα, [Refs 5th c.BC+]; β. λόγον make good one's word, [Refs 5th c.BC+]; treat as valid, τὰς αὑτῶν αἰσθήσεις [Refs 4th c.BC+]; β. τινί τι secure one the possession of a thing, οὐδ᾽ ἡμῖν αὐτοῖς βεβαιόωοῦμεν [τὴν ἐλευθερίαν] [βεβαιόωοῦντες τοὺς νόμους οὒς ἐψηφίσασθε 5th c.BC: Lysias Orator 6.29, compare 4th c.BC: Demosthenes Orator 21.30; τὴν ἀρχήν τινι 1st-2nd c.AD: Plutarchus Biographus et Philosophus “Sulla” 22; τὸν λόγον NT.Mark.16.20 ">NT+5th c.BC+]:—middle, establish for oneself, secure, σφᾶς αὐτούς [Refs 5th c.BC+]; τὴν ἀρχήν, τὴν φιλίαν τινός, [Refs]; β. τινάς confirm them in one's interest,[Refs 2nd c.BC+]

__2 middle, secure one's ground in argument, [Refs 5th c.BC+]; confirm oneself in an opinion, [Refs]
__3 guarantee the validity of a purchase, warrant the purchaser's title, β. τινὶ τὸ βαλανεῖον [Refs 5th c.BC+]; τὴν μίσθωσιν [Refs 1st c.BC+]: generally, β. τοὺς κανόνας [Refs 2nd c.AD+]
__II intransitive, determine, show itself positively, τοῖσιν ἐνδοιαστῶς ἔχουσι.. ἐβεβαίωσε [ νοῦσος] [Refs 5th c.BC+]

LSJ Scripture Refs: Mark.16.20