1 Samuel 2:27
26 However, the boy Samuel was growing up and finding favor both with the Lord and with people. 27 Then a man of God came to Eli and said to him, “This is what the Lord has said: ‘I plainly revealed myself to your ancestor’s house when they were slaves to the house of Pharaoh in Egypt. 28 I chose your ancestor from all the tribes of Israel to be my priest, to offer sacrifice on my altar, to burn incense, and to bear the ephod before me. I gave to your ancestor’s house all the fire offerings made by the Israelites.
2 Samuel 6:14
13 Those who carried the ark of the Lord took six steps and then David sacrificed an ox and a fatling calf. 14 Now David, wearing a linen ephod, was dancing with all his strength before the Lord. 15 David and all Israel were bringing up the ark of the Lord, shouting and blowing trumpets.
LXX 2 Samuel 6:14
13 And there were with him bearing the ark seven bands, and for a sacrifice a calf and lambs. 14 And David sounded with well-tuned instruments before the Lord, and David was clothed with a fine long robe. 15 And David and all the house of Israel brought up the ark of the Lord with shouting, and with the sound of a trumpet.
Notes and References
"... As a member of the tribe of Judah, David cannot be a priest. In Deuteronomy, there is also a distinction between the laws for the king (Deuteronomy 17:14–20) and those for the Levitical priests (Deuteronomy 18:1–8). This necessitates a change in the reproduction of some texts that contradict these rules. When returning the ark of the Lord, David was girded “with the ephod” (2 Samuel 6:14). Both the Septuagint and Targum Jonathan reserve the ephod to priests. In this way, we can explain the rendering by Targum Jonathan (David was girded with a tunic of linen) and the Septuagint (David was girded with a distinguishing garment) ..."
Meiser, Martin The Septuagint and Its Reception: Collected Essays (pp. 77-78) Mohr Siebeck, 2022