God commands it for our own benefit, not because he needs it.
The Bible wasn't written in English.
> The Hebrew word translated into ‘awe’ in the Bible is yirah (יראה, pronounced yir-ah). It often directly translates into fear, like “fear of the Lord,” but it can also mean respect, reverence, and worship.
>John Mallon writes that the "fear" in "fear of the Lord" is often misinterpreted as "servile fear" (the fear of getting in trouble) when it should be understood as "filial fear" (the fear of offending someone whom one loves).
Alas, the majority of Christians are not very "reasonable" in that way today. Fosdick was asking 100 years ago (1922) if the fundamentalists will win[0], and it is pretty clear today that they have[1].
1. https://www.biblegateway.com/passage/?search=Ecclesiastes%20...