Preventing Black's only active idea, ...Na5-c4. Besides which, a doubling of rooks with Rbc2 is enabled.
This simply drops a pawn. Preferable was 2...c6 with just a slight disadvantage – Yusupov.
Unity Chess Club
Radulov - Westerinen Helsinki 1972 White to move
1.Bxb7! Rxb7 2.Nc6!
With every exchange the inferiority of that rook will make itself more strongly felt.
In the event of 4...exf5 , one of several tempting replies is 5.Ne7+! Bxe7 6.Rxe7 , followed by Rdd7.