Charles Simeon, Horae Homileticae, Vol. IX, Discourse 1071 on Jeremiah 31:10–14, 'Blessings from a Preached Gospel' (Internet Archive horaehomileticae183309sime).

Now a mutilated Gospel is in reality no Gospel: salvation must be preached as altogether of grace through faith: the whole glory of it belongs to God: nor will he ever honour any ministry that robs him of it.