John Gill Bible Commentary

Then opened he their understanding,.... He not only opened their hearts, to attend to what he said, and the proofs he gave of his resurrection from the dead in a true body; but he removed the veil from the eyes of their minds, and gave them an understanding of the sacred writings, respecting this matter: that they might understand the Scriptures; concerning his sufferings, death, and resurrection, which they were very ignorant of before, and which were as a sealed book unto them, Joh 20:9 though they had been from their infancy brought up to the reading of the Scriptures, and had had the advantage of Christ's ministry for some years; which shows the necessity of the special illumination of the Spirit, and the influence of his grace to remove the darkness of the mind, and give the true sense of the sacred writings.