Mark 16:20βεβαιοῦντος
And they went out and preached everywhere, and the Lord worked through them, confirming His word by the signs that accompanied it.
Romans 15:8βεβαιῶσαι
For I tell you that Christ has become a servant of the circumcised on behalf of God’s truth, to confirm the promises made to the patriarchs,
1 Corinthians 1:6ἐβεβαιώθη
because our testimony about Christ was confirmed in you.
2 Corinthians 1:21βεβαιῶν
Now it is God who establishes both us and you in Christ. He anointed us,
Colossians 2:7βεβαιούμενοι
rooted and built up in Him, established in the faith as you were taught, and overflowing with thankfulness.
Hebrews 2:3ἐβεβαιώθη
how shall we escape if we neglect such a great salvation? This salvation was first announced by the Lord, was confirmed to us by those who heard Him,

Abbott-Smith

βεβαιόω, -ῶ
(βέβαιος), [in LXX: Ps 40 (41)12 (נצב hi.), 118 (119)28 (קוּם pi.), 3Ma.5:42 * ;]
to confirm, establish, secure, of things (cl.): λόγον, Mk 16:[20]; ἐπαγγελίας, Rom.15:8; of persons (DCG, ii, 605): 1Co.1:8, 2Co.1:21. Pass., 1Co.1:6, Col.2:7, Heb.2:3 13:9 (as an Attic legal term, to guarantee the validity of a purchase, establish or confirm a title; see next word, Cremer, 139; cf. δια-β.).†
(AS)

Sources: Abbott-Smith’s Manual Greek Lexicon of the New Testament (1922, public domain) and glosses from STEPBible TBESG (CC BY 4.0); STEPBible TAGNT (Greek New Testament, CC BY 4.0); the Berean Standard Bible (public domain). Reformatted by Word Study, wording unchanged. All sources and licenses.