Arise; for this matter belongeth unto thee - By the decree of Artaxerxes, he was authorized to do everything that the law of God required: see Ezra 7:23-28. And all officers were commanded to be aiding and assisting; hence Shechaniah says, We are with you.

Arise; for [this] matter (d) [belongeth] unto thee: we also [will be] with thee: be of good courage, and do [it].
(d) Because God has given you authority and learning to persuade the people in this and to command them.

Arise,.... From the ground, where he lay prostrate:
for this matter belongeth unto thee; as a priest and scribe of the law, well versed in it, and therefore could direct what was to be done according to it; and as a ruler under the king of Persia, and a commissioner of his, to inquire whether the law of God was observed by the Jews, Ezra 7:14 and so had authority to put the law in execution:
we also will be with thee; to help and assist in the reformation of this evil:
be of good courage, and do it; do not despair of going through it, though there may be some opposition to it; begin, and doubt not of succeeding.

"Up! for this matter concerns thee (thou art called to carry it out), and we are with thee (will assist thee therein); be strong (courageous) and do it."