vocal samples and legality

Hi, I just have a legal question on vocal samples in original music. I am midi programming a song and at some point toward the end it uses like 4 seconds worth of a repeated vocal from a rather popular rap song. It's pitched up and faster, chopped up a lot too, but I am unsure if a distributor would be ok with that.

Sorry if this question is against the rules. I just want to avoid copyright infringement