Understanding the gift of understanding.
The gift of understanding is the infused gift of the Holy Spirit given to the mind for grasping revealed truths easily and profoundly. It differs from faith because it gives insight into the meaning of what a person believes, whereas faith, as such, merely assents to what God has revealed.
This gift produces three principal effects in those who possess it. They are enabled to penetrate to the very core of revealed truths, without ever fully understanding their meaning; they are confirmed in their belief by acquiring great certitude in the revealed word of God; and they are brought to the knowledge of a greater number of truths by drawing numerous conclusions from revealed principles.