The logical extension of the Reformed polemic against idolatry is that not only should the physical attempt to embody Deity be eliminated but so should mental concepts which attribute a corporeal form to God. Thus the question asked by Petrus van Mastricht (1630-1706) whether God should be conceived as an old man is not a silly or frivolous one. Notwithstanding the negative theology (vie negativa) implied by the Reformed anti-idolatry polemic, it does not leave one to resort to mystical silence in which we can say nothing about God. Instead God’s self-revelation in scripture reveals those positive statements about God that are permissible. This is what Mastricht had to say:
“[Is it right] in divine worship when praying to objectify God to oneself as an ‘old man’?… Because the Lutherans have long since lost the use of images in public worship, which cannot but generate such stupid conceptions in onlookers, they cannot with any sort of επιεικεια [graciousness/forbearance] find fault. They declare that such conceptions of God in the guise of an elderly man do not import any sin, provided they do not insist that God’s essence has such a figure. In order to get at them with both nails the Reformed say that it is lawful to have a concept of God, in fact it is highly necessary, unless we would be atheist; yet they hold that a concept of God under the guise of a man or anything else corporeal is quite out of order. [The reasons are as follows:] (1) The Saviour Jn. 4:24 bids us hold such a conception of God, as agrees with God’s nature, describes God as Spirit and of course He wishes to be worshipped and adored in spirit, i.e., spiritually, without any sort of figures; and in truth, or with true thoughts agreeable to the concept. (2) Such conceptions of God are false, according as they do not agree with the God conceived; in fact they are illicit. (3) Such concepts are vain Rom. 1:21. (4) They obscure the glory of the incorruptible God and as it were change it εν ομοιωματι εικονος φθαρτον ειθρωπον [‘for images resembling a mortal human being’ (Rom. 1:23)]. (5) By these concepts the heart is clouded and the mind rendered foolish.”
– Petrus van Mastricht (1630-1706), Theoretica-practica Theologia, II.iv.12.