Exodus 28:1לְכַהֲנוֹ
“Next, have your brother Aaron brought to you from among the Israelites, along with his sons Nadab, Abihu, Eleazar, and Ithamar, to serve Me as priests.
Leviticus 7:35לְכַהֵן
This is the portion of the food offerings to the LORD for Aaron and his sons since the day they were presented to serve the LORD as priests.
Numbers 3:3לְכַהֵן
These were Aaron’s sons, the anointed priests, who were ordained to serve as priests.
Deuteronomy 10:6וַיְכַהֵן
The Israelites traveled from Beeroth Bene-jaakan to Moserah, where Aaron died and was buried, and Eleazar his son succeeded him as priest.
1 Chronicles 6:10כִּהֵן
Johanan was the father of Azariah, who served as priest in the temple that Solomon built in Jerusalem,
2 Chronicles 11:14מִכַּהֵן
For the Levites left their pasturelands and their possessions and went to Judah and Jerusalem, because Jeroboam and his sons had rejected them as priests of the LORD.

Brown-Driver-Briggs

[כָּהַן] vb. only Pi. denom. act as priest

Sources: Brown-Driver-Briggs (1906, public domain) from the Open Scriptures Hebrew Lexicon (CC BY 4.0), glosses from STEPBible TBESH (CC BY 4.0); STEPBible TAHOT (Hebrew Bible, Leningrad Codex, CC BY 4.0); the Berean Standard Bible (public domain). Reformatted by Word Study, wording unchanged. All sources and licenses.