And grandma sad when she saw my commercial
"Stop having people at your shows that wasn't at rehearsals"

from Big Sean (Ft. James Fauntleroy & Nicole Lequerica) – Fire Lyrics on Rap Genius

Meaning

When Big Sean’s grandmother saw the Adidas commercial that he appeared in, she voiced her disapproval.
http://www.youtube.com/watch?v=9pRU2bDAdms She told him that he should only spend time with the people who were there for him when he wasn’t rich and famous. Lots of people try to make friends with celebrities for the wrong reasons, so Big Sean’s grandmother is saying that he should be loyal to the friends who have been with him for a long time and are friends for the right reasons. Keep your circle tight, basically.
This was the primary subject of the second single off Hall of Fame, Switch Up

Sean talks about these lines here

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