9 I have said who was the exhorter, namely, that lover who would not alone embrace what he loves, and says, “Approach unto Him, and be ye lightened”. For he says what he himself proved. For some spiritual person in the Body of Christ, or even our Lord Jesus Christ Himself according to the flesh, the Head exhorting His Own Members, says; what? “Approach unto Him, and be ye lightened.” Or rather some spiritual Christian invites us to approach to our Lord Jesus Christ Himself.
But let us approach to Him and be lightened; not as the Jews approached to Him, that they might be darkened; for they approached to Him that they might crucify Him: let us approach to Him that we may receive His Body and Blood. They by Him crucified were darkened; we by eating and drinking The Crucified are lightened. “Approach unto Him, and be ye lightened.” Lo, this is said to the Gentiles. Christ was crucified amid the Jews raging and seeing; the Gentiles were absent; lo, they have approached who were in darkness, and they who saw not are lightened.
Whereby approach the Gentiles? By following with faith, by longing with the heart, by running with charity. Your feet are your charity. Have two feet, be not lame. What are your two feet? The two commandments of love, of your God, and of your Neighbour. With these feet run thou unto God, approach unto Him, for He has both exhorted you to run, and has Himself shed His Own Light, as he has magnificently and divinely continued. “And your faces shall not be ashamed.” “Approach” (says he) “unto Him, and be ye lightened; and your faces shall not be ashamed.”
No face shall be ashamed but of the proud. Wherefore? Because he would be lifted up, and when he has suffered insult, or ignominy, or mischance in this world, or any affliction, he is ashamed. But fear not thou, approach unto Him, and you shall not be ashamed....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)