Matthew 5:21ἀρχαίοις
You have heard that it was said to the ancients, ‘Do not murder’ and ‘Anyone who murders will be subject to judgment.’
Luke 9:8ἀρχαίων
others that Elijah had appeared, and still others that a prophet of old had arisen.
Acts 15:7ἀρχαίων
After much discussion, Peter got up and said to them, “Brothers, you know that in the early days God made a choice among you that the Gentiles would hear from my lips the message of the gospel and believe.
2 Corinthians 5:17ἀρχαῖα
Therefore if anyone is in Christ, he is a new creation. The old has passed away. Behold, the new has come!
2 Peter 2:5ἀρχαίου
if He did not spare the ancient world when He brought the flood on its ungodly people, but preserved Noah, a preacher of righteousness, among the eight;
Revelation 12:9ἀρχαῖος
And the great dragon was hurled down—that ancient serpent called the devil and Satan, the deceiver of the whole world. He was hurled to the earth, and his angels with him.

Abbott-Smith

ἀρχαῖος, -αία, -αῖον
(ἀρχή), [in LXX chiefly for קֶדֶם ;]
original, ancient: Mat.5:21, 33, Luk.9:8, 19, Act.15:7, 21 21:16, 2Co.5:17, 2Pe.2:5, Rev.12:9 20:2.†
SYN.: παλαιός, old, without the reference to beginning and origin contained in ἀ. The distinction is observed in π. (MM, see word). ἀ. is the antithesis to καινός: παλ. to vέος (see Westc., He., 223; Cremer, 116)
(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.