Charles Ellicott Commentary 1 Chronicles 19:13

"Be of good courage, and let us play the man for our people, and for the cities of our God: and Jehovah do that which seemeth him good." — 1 Chronicles 19:13 (ASV)

Be of good courage. —The same verb was rendered “be strong” in 1 Chronicles 19:12.

Let us behave ourselves valiantly. —The same verb again, in reflexive form. Thus the whole runs literally: Be strong, and let us show ourselves strong!

And let the Lord do... —Literally, And Jehovah — the good in his own eyes may he do! The order in the Hebrew of Samuel is that of the Authorised Version here. The chronicler lays stress on the auspicious word “good.” There is also emphasis on Jehovah, as leaving the issue in His hands who is Lord of hosts and God of battles; and on the verb, expressive of a pious wish that right may not miscarry. Evidently, the spirit which inspired the prayer, Thy will be done, was not unknown to the warriors of the old theocracy.