It's a sample of Seven Minutes of Funk by Tyrone Davis and The Whole Darn Family
EPMD was the first one to use the sample in 1987 for their first single It's My Thing.
Hip Hop, in general, is samping records from the 70s and rapping over the beats. In the late 70s and early 80s DJs would have two copies of the same record and keep the beat going on turntables. Then in the 80s, the sampler was invented and people started looping the breaks that DJs used to cut and paste on two turntables.
All Jay Z did was sample the Seven Minutes of Funk beat.
So to claim that Busta Rhymes, or Timbaland, didn't "change the beat" is nonsense, he wasn't supposed to change the beat, he was supposed to rap over it exactly like it is.