John Wesley on Revelation 2:23

And I will kill her children - Those which she hath borne in adultery, and them whom she hath seduced. With death - This expression denotes death by the plague, or by some manifest stroke of God's hand. Probably the remarkable vengeance taken on her children was the token of the certainty of all the rest. And all the churches - To which thou now writest. Shall know that I search the reins - The desires. And hearts - Thoughts.