6. If we have understood this, thanks be to God; but if any has not sufficiently understood, man has done as far as he could: as for the rest, let him see whence he may hope to understand. As laborers outside, we can plant and water; but it is of God to give the increase. "My doctrine," saith He, "is not mine, but His that sent me." Let him who says he has not yet understood hear counsel. For since it was a great and profound matter that had been spoken, the Lord Christ Himself did certainly see that all would not understand this so profound a matter, and He gave counsel in the sequel. Dost thou wish to understand? Believe. For God has said by the prophet: "Except ye believe, ye shall not understand." To the same purpose what the Lord here also added as He went on "If any man is willing to do His will, he shall know concerning the doctrine, whether it be of God, or whether I speak from myself." What is the meaning of this, "If any man be willing to do His will"? But I had said, if any man believe; and I gave this counsel: If thou hast not understood, said I, believe. For understanding is the reward of faith. Therefore do not seek to understand in order to believe, but believe that thou mayest understand; since, "except ye believe, ye shall not understand." Therefore when I would counsel the obedience of believing toward the possibility of understanding, and say that our Lord Jesus Christ has added this very thing in the following sentence, we find Him to have said, "If any man be willing to do His will, he shall know of the doctrine." What is "he shall know"? It is the same thing as "he shall understand." But what is "If any man be willing to do His will"? It is the same thing as to believe. All men indeed perceive that "shall know" is the same thing as "shall understand:" but that the saying, "If any man be willing to do His will," refers to believing, all do not perceive; to perceive this more accurately, we need the Lord Himself for expounder, to show us whether the doing of the Father's will does in reality refer to believing. But who does not know that this is to do the will of God, to work the work of God; that is, to work that work which is pleasing to Him? But the Lord Himself says openly in another place: "This is the work of God, that ye believe on Him whom He has sent." "That ye believe on Him," not, that ye believe Him. But if ye believe an Him, ye believe Him; yet he that believes Him does not necessarily believe on Him. For even the devils believed Him, but they did not believe on Him. Again, moreover, of His apostles we can say, we believe Paul; but not, we believe on Paul: we believe Peter; but not, we believe on Peter. For, "to him that believeth on Him that justifieth the ungodly, his faith is counted unto him for righteousness." What then is "to believe on Him"? By believing to love Him, by believing to esteem highly, by believing to go into Him and to be incorporated in His members. It is faith itself then that God exacts from us: and He finds not that which He exacts, unless He has bestowed what He may find. What faith, but that which the apostle has most amply defined in another place, saying, "Neither circumcision availeth anything, nor uncircumcision, but faith that worketh by love?" Not any faith of what kind soever, but "faith that worketh by love:" let this faith be in thee, and thou shall understand concerning the doctrine. What indeed shall thou understand? That "this doctrine is not mine, but His that sent me;" that is, thou shall understand that Christ the Son of God, who is the doctrine of the Father, is not from Himself, but is the Son of the Father.
