Deuteronomy 30:14

True knowledge, then, consists in the understanding of Christ, which Paul terms the wisdom of God hidden in a mystery, which “the natural man receiveth not,” the doctrine of the cross; of which if any man “taste,” he will not accede to the disputations and quibbles of proud and puffed-up men, who go into matters of which they have no perception. For the truth is unsophisticated ( ἀσχημάτιστος ); and “the word is nigh thee, in thy mouth and in thy heart,” as the same apostle declares, being easy of comprehension to those who are obedient. …

But “the precepts of the law are very good,” if we use them lawfully. Indeed, by the very fact (of which we have the firmest conviction) “that the just and good God could not possibly have enjoined impossibilities,” we are admonished both what to do in easy paths and what to ask for when they are difficult. Now all things are easy for love to effect, to which (and which alone) “Christ’s burden is light,”, or rather, it is itself alone the burden which is light. Accordingly it is said, “And His commandments are not grievous;” so that whoever finds them grievous must regard the inspired statement about their “not being grievous” as having been capable of only this meaning, that there may be a state of heart to which they are not burdensome, and he must pray for that disposition which he at present wants, so as to be able to fulfil all that is commanded him. …

He afterwards adduces those passages which represent God as recommending His own commandments as not grievous: let us now attend to their testimony. “Because,” says he, “God’s commandments are not only not impossible, but they are not even grievous. In Deuteronomy: ‘The Lord thy God will again turn and rejoice over thee for good, as He rejoiced over thy fathers, if ye shall hearken to the voice of the Lord your God, to keep His commandments, and His ordinances, and His judgments, written in the book of this law; if thou turn to the Lord thy God with all thine heart, and with all thy soul. …

The tenets we have been speaking of have been proved to be nothing more than a false guide for life; but the way of truth will aim at reaching the real and true God. But for its knowledge and accurate comprehension, there is need of none other save of ourselves. Neither as God Himself is above all, is the road to Him afar off or outside ourselves, but it is in us and it is possible to find it from ourselves, in the first instance, as Moses also taught, when he said: “The word” of faith “is within thy heart.” Which very thing the Saviour declared and confirmed, when He said: “The kingdom of God is within you.” 2. For having in ourselves faith, and the kingdom of God, we shall be able quickly to see and perceive the King of the Universe, the saving Word of the Father. …

70. But there is demanded from us an unwavering certainty. The Apostle expounding the whole secret of the Scripture passes on, Thy word is nigh, in thy mouth and in thy heart . The words of our confession must not be tardy or deliberately vague: there must be no interval between heart and lips, lest what ought to be the confession of true reverence become a subterfuge of infidelity. The word must be near us, and within us; no delay between the heart and the lips; a faith of conviction as well as of words. Heart and lips must be in harmony, and reveal in thought and utterance a religion which does not waver. Here too, as before, the Apostle adds the explanation of the Prophet’s words, That is the word of Faith, which we preach; because if thou shalt confess with thy mouth Jesus as Lord, and shalt believe in thy heart that God hath raised Him up from the dead, thou shalt be saved . …

14. Let us then not keep the Lord’s money buried and hidden in the flesh; nor let us hide our one talent in a napkin; but like good money-changers let us ever weigh it out with labour of mind and body, with an even and ready will, that the word may be near, even in thy mouth and in thy heart.