2 Chronicles 29:34

Only, the priests have become few, and have not been able to strip the whole of the burnt-offerings, and their brethren the Levites strengthen them till the completion of the work, and till the priests sanctify themselves, for the Levites are more upright of heart to sanctify themselves than the priests.

2 Chronicles 30:3

for they have not been able to make it at that time, for the priests have not sanctified themselves sufficiently, and the people have not been gathered to Jerusalem.

2 Chronicles 35:11

and they slaughter the passover-offering, and the priests sprinkle out of their hand, and the Levites are striping;

Numbers 8:15

and afterwards do the Levites come in to serve the tent of meeting, and thou hast cleansed them, and hast waved them -- a wave-offering.

Numbers 8:19

'And I give the Levites gifts to Aaron and to his sons, from the midst of the sons of Israel, to do the service of the sons of Israel in the tent of meeting, and to make atonement for the sons of Israel, and there is no plague among the sons of Israel in the sons of Israel's drawing nigh unto the sanctuary.'

Numbers 18:3

'And they have kept thy charge, and the charge of all the tent; only, unto the vessels of the sanctuary and unto the altar they do not come near, and they die not, either they or you;

Numbers 18:6-7

'And I, lo, I have taken your brethren the Levites from the midst of the sons of Israel; to you a gift they are given by Jehovah, to do the service of the tent of meeting;

1 Chronicles 29:17

'And I have known, my God, that Thou art trying the heart, and uprightness dost desire; I, in the uprightness of my heart, have willingly offered all these: and now, Thy people who are found here I have seen with joy to offer willingly to Thee.

2 Chronicles 29:5

And he saith to them, 'Hear me, O Levites, now, sanctify yourselves, and sanctify the house of Jehovah, God of your fathers, and bring out the impurity from the sanctuary,

2 Chronicles 30:16-17

And they stand on their station according to their ordinance; according to the law of Moses the man of God the priests are sprinkling the blood out of the hand of the Levites,

Psalm 7:10

My shield is on God, Saviour of the upright in heart!

Psalm 26:6

I wash in innocency my hands, And I compass Thine altar, O Jehovah.

Psalm 94:15

For to righteousness judgment turneth back, And after it all the upright of heart,

Treasury of Scripture Knowledge

Summary

But the priests were too few, so that they could not flay all the burnt offerings: wherefore their brethren the Levites did help them, till the work was ended, and until the other priests had sanctified themselves: for the Levites were more upright in heart to sanctify themselves than the priests.

For the levites

Bible References

Their brethren

2 Chronicles 35:11
and they slaughter the passover-offering, and the priests sprinkle out of their hand, and the Levites are striping;
Numbers 8:15
and afterwards do the Levites come in to serve the tent of meeting, and thou hast cleansed them, and hast waved them -- a wave-offering.
Numbers 18:3
'And they have kept thy charge, and the charge of all the tent; only, unto the vessels of the sanctuary and unto the altar they do not come near, and they die not, either they or you;

For the levites

2 Chronicles 30:3
for they have not been able to make it at that time, for the priests have not sanctified themselves sufficiently, and the people have not been gathered to Jerusalem.

Upright

1 Chronicles 29:17
'And I have known, my God, that Thou art trying the heart, and uprightness dost desire; I, in the uprightness of my heart, have willingly offered all these: and now, Thy people who are found here I have seen with joy to offer willingly to Thee.
Psalm 7:10
My shield is on God, Saviour of the upright in heart!
Psalm 26:6
I wash in innocency my hands, And I compass Thine altar, O Jehovah.
Psalm 94:15
For to righteousness judgment turneth back, And after it all the upright of heart,