Those promises were for Israel. They don't apply to the church.

God made this promise to Israel:

(Exodus 15:26 NIV) He said, "If you listen carefully to the voice of the LORD your God and do what is right in his eyes, if you pay attention to his commands and keep all his decrees, I will not bring on you any of the diseases I brought on the Egyptians, for I am the LORD, who heals you."

It should be obvious that that promise doesn't apply to the church. My first wife died from kidney disease.