It was he who sent the "peace flotilla" to challenge Israel's right to blockade Gaza (recognized under international law and explicitly by the U.N.). He made the inevitable violent result of that adventure into an anti-Israeli cause célèbre. He has now announced that the next peace flotilla will be accompanied by the Turkish navy.
This will put Israel in the position of either surrendering its right to defend itself, or firing on Turkish naval vessels.
There is no way to overstate the gravity of this: Erdogan is manoeuvring to create a casus belli.