Lord's Supper Vs. Rome's Mass

'That doctrine which maintains a change of the substance of bread and wine into the substance of Christ's body and blood (commonly called transubstantiation) by consecration of a priest, or by any other way, is repugnant,not to Scripture alone, but even to common sense and reason; overthroweth the nature of the sacrament, and hath been, and is the cause of manifold superstitions; yea, of gross idolatries.' Westminster Confession of Faith 29:6