The seemingly exaggerated repetition of the phrase listed according to the commandments of the Lord
(Numbers 4:37, Numbers 4:41, Numbers 4:45, Numbers 4:49) signals that a conclusion is being reached in the narrative. (Musical compositions often employ the same type of exaggerated repetition to signal that the work is reaching a conclusion.)
The glorious task that was given to Moses to conduct a census (from Nimbers 1 onwards) is now completed. The repetitions signal the conclusions of this task and, thereby, the reader anticipates a transition to another section in the book of Numbers.
37 This was the list of the clans of the Kohathites, all who served in the tent of meeting, whom Moses and Aaron listed according to the commandment of the LORD by Moses.