The Catholic Church recognizes seven gifts of the Holy Spirit; a listing of these gifts is found in Isaiah 11:2-3. (Saint Paul writes of "manifestations of the Spirit" in 1 Corinthians 12:7-11, and some Protestants use that list to come up with nine gifts of the Holy Spirit, but these are not the same as the ones recognized by the Catholic Church.)
The seven gifts of the Holy Spirit are present in their fullness in Jesus Christ, but they are also found in all Christians who are in a state of grace. We receive them when we are infused with sanctifying grace, the life of God within us—as, for example, when we receive a sacrament worthily. We first receive the seven gifts of the Holy Spirit in the Sacrament of Baptism; these gifts are strengthened in the Sacrament of Confirmation, which is one of the reasons why the Catholic Church teaches that confirmation is properly viewed as the completion of baptism.
As the current Catechism of the Catholic Church (para. 1831) notes, the seven gifts of the Holy Spirit "complete and perfect the virtues of those who receive them." Infused with His gifts, we respond to the promptings of the Holy Spirit as if by instinct, the way Christ Himself would.
π Wisdom:
According to Catholic doctrine, wisdom is one of the seven gifts of the Holy Spirit, which are enumerated in Isaiah 11:2–3. These gifts are present in their fullness in Jesus Christ, Whom Isaiah foretold (Isaiah 11:1). From the Catholic perspective, the faithful receive the seven gifts from God—who is within each of us. They express that inward grace by outward expressions of the sacraments. These gifts are intended to convey the essence of God the Father's plan for salvation, or, as the current Catechism of the Catholic Church (para. 1831) puts it, "They complete and perfect the virtues of those who receive them."
π Understanding:
Understanding is the second of the seven gifts of the Holy Spirit enumerated in Isaiah 11:2-3, behind only wisdom. It differs from wisdom in that wisdom is the desire to contemplate the things of God, while understanding allows us, as Fr. John A. Hardon writes in his Modern Catholic Dictionary, to "penetrate to the very core of revealed truths." This doesn't mean that we can come to understand, say, the Trinity the way that we might a mathematical equation, but that we become certain of the truth of the doctrine of the Trinity. Such certitude moves beyond faith, which "merely assents to what God has revealed."
π Counsel:
Counsel, the third of the seven gifts of the Holy Spirit enumerated in Isaiah 11:2-3, is the perfection of the cardinal virtue of prudence. While prudence, like all the cardinal virtues, can be practiced by anyone, whether in a state of grace or not, it can take on a supernatural dimension through sanctifying grace. Counsel is the fruit of this supernatural prudence.
Like prudence, counsel allows us to judge rightly what we should do in a particular circumstance. It goes beyond prudence, though, in allowing such judgments to be made promptly, "as by a sort of supernatural intuition," as Fr. John A. Hardon writes in his Modern Catholic Dictionary. When we are infused with the gifts of the Holy Spirit, we respond to the promptings of the Holy Spirit as if by instinct.
π Fortitude:
Fortitude is one of the four cardinal virtues. That means that the virtue of fortitude can be practiced by anyone, Christian or not, since, unlike the theological virtues, the cardinal virtues are not, in themselves, the gifts of God through grace but the outgrowth of habit.
The virtue of fortitude is commonly called courage, but it is different from what much of what we think of as courage today. Fortitude is always reasoned and reasonable; the person exercising fortitude is willing to put himself in danger if necessary, but he does not seek danger for danger's sake. Fortitude always serves a higher purpose.
π Knowledge:
The fifth gift of the Holy Spirit, knowledge, is often confused with both wisdom and understanding. Like wisdom, knowledge is the perfection of faith, but whereas wisdom gives us the desire to judge all things according to the truths of the Catholic Faith, knowledge is the actual ability to do so. Like counsel, it is aimed at our actions in this life. In a limited way, knowledge allows us to see the circumstances of our life the way that God sees them. Through this gift of the Holy Spirit, we can determine God's purpose for our lives and live them accordingly.
π Piety:
Piety, the sixth gift of the Holy Spirit, is the perfection of the virtue of religion. While we tend to think of religion today as the external elements of our faith, it really means the willingness to worship and to serve God. Piety takes that willingness beyond a sense of duty so that we desire to worship God and to serve Him out of love, the way that we desire to honor our parents and do what they wish.
π Fear of the Lord:
The seventh and final gift of the Holy Spirit is the fear of the Lord, and perhaps no other gift of the Holy Spirit is so misunderstood. We think of fear and hope as opposites, but the fear of the Lord confirms the theological virtue of hope. This gift of the Holy Spirit gives us the desire not to offend God, as well as the certainty that God will supply us the grace that we need in order to keep from offending Him. Our desire not to offend God is more than simply a sense of duty; like piety, the fear of the Lord arises out of love.