The friend with the back problem cure is presupposing his pastor is affiliated with the One True Faith.
Many, many people of different faiths have made similar (or better) claims of cures. Obviously, there is only One True Faith, so we have either many people LYING or deceived by SATAN.
Many, many people of different faiths have made similar (or better) claims of cures. Obviously, there is only One True Faith, so we have either many people LYING or deceived by SATAN.