For the priests and the Levites were purified together, all of them were pure, and killed the passover for all the children of the captivity, and for their brethren the priests, and for themselves. The Levites were purified together - They were all ready at one time to observe the proper rites and ceremonies, and had no need of having a second passover, which was appointed by the law for those who had been accidentally defiled, or were at a distance from the tabernacle. See 2 Chronicles 30:3.
Related Commentaries of Ezra 6:20
Ezra 6:20
20 For the priests and the Levites were purified together, all of them were pure, and killed the passover for all the children of the captivity, and for their brethren the priests, and for themselves.