Philoxenus of Mabbug

"He that would draw nigh to God is bound to believe that He is, and [that] to those who seek Him He will be a rewarder;" this law hath Paul committed to the man who wisheth to draw nigh to God, and this obligation of rewarding [him] is laid upon God. He must believe only that God is, and whosoever believeth that He is, from what time and in what manner [He existeth] he will not enquire. So also is it with His will, if he heareth [it], and His word, and His doctrine; that it is the will of God Himself he will be sure, and the voice and commandment of God he will hearken unto and believe. That he should judge why, and in what form, and for what reason [He is] thus is the insolent investigation of the soul which hath not perceived God.

Observe then how great is the power of faith, for all the spiritual things which are would, without it, be as if they existed not; and not only living works or spiritual countries, but that Being which is, would be, if we had no faith, as if He existed not. For this reason Paul looked upon the mystery of our doctrine, and said, "He that would draw nigh to God is bound to believe that He is;" he commanded the disciple [first] to take faith upon himself, and then to draw nigh to the discipleship of Christ. For Paul knew that the spiritual nature could not fall under the bodily senses, and that it could not be known, for not even one of the bodily senses could subjugate it, and for this reason he commanded us in his doctrine to believe only that He is.