Exodus 19:6
5 And now, if you will diligently listen to me and keep my covenant, then you will be my special possession out of all the nations, for all the earth is mine, 6 and you will be to me a kingdom of priests and a holy nation.’ These are the words that you will speak to the Israelites.” 7 So Moses came and summoned the elders of Israel. He set before them all these words that the Lord had commanded him,
Onkelos Exodus 19:6
5 and now, if by listening you will accept My memra, and will keep My covenant, you, before Me, shall be more beloved than all peoples; for all the earth is Mine. 6 And you, before Me, shall be kings, priests, a holy people. These are the words which thou shalt speak with the sons of Israel. 7 And Moses came, and called the elders of the people, and set all these words in order before them, as the Lord had instructed him.
Notes and References
"... The Bible describes the Israelites in verse 19:6 as 'a kingdom of priests and a holy nation.' Virtually all early biblical translations, including Onkelos, view the words 'kingdom' and 'priests' as two separate promises. This interpretation may have been prompted by the idea that priests should not function as kings ..."
Drazin, Israel, and Stanley M. Wagner Onkelos on the Torah, Exodus: Understanding the Bible Text (p. 122) Gefen, 2006