The Lord put the blessing upon the MC
O to the M, dreams were spoken to him
That's when I knew my flows would overflow to the rim
Open my eyes, yes sir this is what I'm made for

from Common – Blue Sky Lyrics on Rap Genius

His flow overflows boundaries and limits like water at the rim of a glass or bowl. Also, to the rim sets up a reference to the D. Wade/D. Rose hard in the paint basketball line that appears later in the verse.

In continuing with the religious references, this line alludes to Psalms 23:4-23:5 which say,

Yea, though I walk through the valley of the shadow of death, I will fear no evil: for thou art with me; thy rod and thy staff they comfort me.

Thou preparest a table before me in the presence of mine enemies: thou anointest my head with oil; my cup runneth over.

The line, “O to the M, dreams were spoken to him” could be a reference to one of the following:
Otis Moss III, a preacher on the southside of Chicago. Common would very familiar with him, having attended and freestyled at his church — the same church President Obama attended
God Himself (being a play on the abbreviation “OMG”).

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