Exodus 19:22

And let the priests also, which come near to the LORD, sanctify themselves, lest the LORD break forth upon them.

Let the priests also, which come hear to the Lord, sanctify themselves. Who these priests were-whether the first-born of families (cf. Exodus 24:5), or the sacerdotal office was at this transitional period conjoined with the exercise of their magisterial functions by the elders of Israel-is not known; but they were not to be so lifted up with pride by the official character which they possessed as to deem themselves better than others, and more worthy to approach the sacred shrine on the mount.