John 11:55ἁγνίσωσιν
Now the Jewish Passover was near, and many people went up from the country to Jerusalem to purify themselves before the Passover.
Acts 21:24ἁγνίσθητι
Take these men, purify yourself along with them, and pay their expenses so they can have their heads shaved. Then everyone will know that there is no truth to these rumors about you, but that you also live in obedience to the law.
James 4:8ἁγνίσατε
Draw near to God, and He will draw near to you. Cleanse your hands, you sinners, and purify your hearts, you double-minded.
1 Peter 1:22ἡγνικότες
Since you have purified your souls by obedience to the truth so that you have a genuine love for your brothers, love one another deeply, from a pure heart.
1 John 3:3ἁγνίζει
And everyone who has this hope in Him purifies himself, just as Christ is pure.

Abbott-Smith

ἁγνίζω (> ἁγνός),
[in LXX always ceremonially, chiefly for קָדַשׁ ;]
to purify, cleanse from defilement;

(b) morally: Jas.4:8, 1Pe.1:22, 1Jn.3:3.
†
SYN.: καθαρίζω, which see (and see: ἁγνός).
(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.