Why Bc3 is suggested by stockfish?

I had this position in a game - 2r1r1k1/1pqbbppp/pn2pn2/4N3/2PP4/1P4P1/PBN1Q1BP/2R2RK1 w - - 7 17

I played Ne3 with the idea of Ng4. But stockfish suggests Bc3. What is the idea behind this?