Knowledge of spiritual things is well distinguished into intellectual and practical: the first has its seat in the mind, the latter in the heart. This latter, divines call a knowledge peculiar to saints; and, in the apostle's dialect, it is "The eminency, or excellency of the knowledge of Christ."And indeed, there is but little excellency in all those petty notions which furnish the lips with discourse, unless by a sweet and powerful influence they draw the conscience and will to the obedience of Christ.
Light in the mind is necessarily antecedent to the sweet and heavenly motions and elevations of the affections: For the farther any man stands from the light of truth, the farther he must needs be from the heat of comfort. Heavenly quickening are begotten in the heart, while the sun of righteousness spreads the beams of truth into the understanding, and the soul sits under those its wings; yet all the light of the gospel spreading and diffusing itself into the mind, can never savingly open and change the heart, without another act of Christ upon it; and what that is, the text informs you;
"Then opened HE their understandings, that they might understand the scriptures".
In which words we have both an act of Christ upon the disciples' understandings, and the immediate end and scope of that act.
1. Christ's act upon their understandings: He opened their understandings. By understanding is not here meant the mind only, in opposition to the heart, will, and affections, but these were opened by and with the mind. The mind is to the heart, as the door to the house: what comes in to the heart, comes in at the understanding, which is introductive to it; and although truths sometimes go no farther than the entry, never penetrate the hearts, yet, here, this effect is undoubtedly included.
Expositors make this expression parallel to that in Acts 16:14. "The Lord opened the heart of Lydia." And it is well observed, that it is one thing to open the scriptures, that is, to expound them, and give the meaning of them, as Paul is said to do in Acts 18:3, and another thing to open the mind or heart, as it is here.
There are, as a learned man truly observes, two doors of the soul barred against Christ; the understanding by ignorance; and the heart by hardness: both these are opened by Christ. The former is opened by the preaching of the gospel, the other by the internal operation of the Spirit. The former belongs to the first part of Christ's Prophetic office, opened in the foregoing sermon: the latter, to that special internal part of his Prophetic office, to be opened in this.
And that it was not a naked act upon their minds only, but that their hearts and minds did work in fellowship, being both touched by this act of Christ, is evident enough by the effects mentioned, ver. 52, 53. "They returned to Jerusalem with great joy, and were continually in the temple, praising and blessing God."
It is confessed, that before this time Christ had opened their hearts by conversion; and this opening is not to be understood simply, but secundum quid, in reference to those particular truths, in which, until now, they were not sufficiently informed, and so their hearts could not be duly affected with them.
They were very dark in their apprehensions of the death and resurrection of Christ; and consequently their hearts were sad and dejected about that which had befallen him, ver. 17. But when he opened the scriptures and their understandings and hearts together, then things appeared with another face, and they returned, blessing and praising God."To the spiritual illumination of a soul, it suffices not that the object be revealed, nor yet that man, the subject of that knowledge have a due use of his own reason; but it is further necessary that the grace and special assistance of the holy Spirit be superadded, to open and mollify the heart, and so give it a due taste and relish of the sweetness of spiritual truth.
"By opening the gospel, he reveals truth to us, and, by opening the heart, in us. Now, though this cannot be without that, yet it is much more excellent to have truth revealed in us, than to us. This divines call praecipuum illud "apogelesma" muneris prophetici; "the principal perfective effect of the Prophetic office," the special blessing promised in the new covenant, Heb. 8:10. "I will put my laws in their mind, and write them in their hearts."