That knowledge of the law is given by the guidance and illumination of the Lord.
The knowledge also of the law itself they daily endeavour to gain not by diligence in reading, but by the guidance and illumination of God as they say to Him: “Show me Your ways, O Lord, and teach me Your paths:” and “open my eyes: and I shall see the wondrous things of Your law:” and “teach me to do Your will, for You are my God;” and again: “Who teaches man knowledge.”
Source: Conferences (New Advent)