He was king—i.e., not Moses but the Lord became king.

Verses 4-5

“[Of] the law which Moses commanded us,
The inheritance of the congregation of Jacob,
When he (Moses) was king in Jes…

Here is his blessing, Let Reuben live. Reuben's great sin had lost him his birthright, yet Moses gives him as much of his blessing as he c…

And he was king in Jeshurun
That is, in Israel, or over the people of Israel, of which name of theirs, (See Gill…

To all his precepts, warnings, and prophecies, Moses added a solemn blessing. He begins with a description of the glorious appearances of God in gi…