Faith is the theological virtue by which we believe in God and all that He has said and revealed (CCC 1814). Infused by God into the souls of the faithful, this supernatural gift enables humans to act as His children and merit eternal life (CCC 1813). Faith is not a matter of believing in mere formulas or propositions, but rather in the realities those expressions convey (CCC 170). It is a personal and free response to God’s initiative and revelation, bringing a superabundant light to the person searching for the ultimate meaning of life (CCC 143, 166).

This virtue is essential for salvation and is the only means by which one can please God (Hebrews 11:6, CCC 161). The righteousness of God is manifested apart from the law and is achieved through faith in Jesus Christ, a free gift that justifies all who believe regardless of their background (Rom 3:21-24). This principle of justification by faith is extended to the Gentiles, fulfilling the promise made to Abraham (Gal 3:6-14). Through faith in Jesus, a person is justified and saved (Rom 10:9-10, CCC 1991), a process that brings peace with God and access to His grace (Rom 5:1).

While justification is achieved through faith, faith and works are complementary aspects of this process. Faith without works is dead (James 2:17, 26), as demonstrated by Abraham, who was justified by his works when he offered Isaac on the altar (Genesis 22:1-14, James 2:21-23). Consequently, faith must be accompanied by works to fully unite the believer to Christ (CCC 1814-1815). This relationship ensures that the moral life, which originates from faith in God (CCC 2087), is expressed through charitable living and love for one another (CCC 170-171).

Faith exists in harmony with reason, as both originate from God and cannot contradict one another (CCC). While reason can achieve some understanding of divine mysteries through analogy, it cannot penetrate them fully, making faith necessary to comprehend truths that surpass human reason (CCC 159-160). Similarly, faith and science are separate but not in conflict; faith concerns divine realities unknown to science, while science deals with the reality of phenomena (CCC).

The exercise of faith requires the interior help of the Holy Spirit, as it is impossible to confess that Jesus is Lord without the Spirit’s touch (683). The Holy Spirit perfects faith through various gifts, enabling a more profound understanding of Revelation (CCC 159). The Church further supports this virtue by bearing, nourishing, and sustaining faith (CCC 169). Through the Magisterium, the Church guards the Sacred deposit of faith contained in Scripture and Tradition (CCC 84) and provides the Creed as a normative summary of the principal truths of the faith (CCC 185-188).

In practice, the obedience of faith involves a free submission to God’s word, as exemplified by Abraham and Mary, who believed that nothing is impossible with God (Hebrews 11:1, Luke 1:37, CCC 274). This faith is strengthened by the assurance of Christ’s foreordained parousia and is maintained through perseverance despite afflictions, leading to the possession of the unshakable kingdom of God (Hebrews 11:1-40, 12:14-29). Furthermore, faith is a prerequisite for a vital and personal relationship with God through prayer (2558) and allows the believer to comprehend the breadth and depth of God’s love (Eph 3:18-19, CCC 1712).

Despite its necessity, faith can be compromised. Sins against faith include voluntary or involuntary doubt and incredulity, which can lead to spiritual blindness (CCC 2088). A lack of faith often manifests in a person’s actual preferences and priorities, revealing a heart that does not yet possess the humility to acknowledge that apart from Christ, nothing can be done (CCC 2732, John 15:5).