Believers are often exhorted to “let go and let God,” to be entirely passive in their sanctification (growth in holiness). The best intentions lie behind this advice. After all, we know that our works contribute nothing to our righteous standing before the Lord (Gal. 2:15–16; Eph. 2:8–9); thus, many people think that giving ourselves a role in sanctification comes perilously close to denying grace.
Certainly it is easy to confuse the process of sanctification with the once-for-all declaration of justification. Even Protestants might believe, implicitly, that our works secure our place in heaven or make God love us more than believers who are “further behind” in their sanctification. To avoid this problem, we simply need to maintain the biblical distinction between justification and sanctification. It is unnecessary to deny our role in sanctification altogether. God’s justification of a person, the starting point of Christian living, relies solely on the work of Christ (2 Cor. 5:21). Sanctification, Ephesians 4:23–24 explains, requires cooperation between the Lord and individual believers.
God’s “job” is to renew our minds. Note the passive voice in verse 23: we are to “be renewed [by the Lord].” He performs the work of inward transformation, renewing our affection for Him and giving us an ever-deepening understanding of His ways. The Lord works through means to accomplish this — personal Bible study, the preached Word of God, the sacraments, prayer — but He performs the work of transformation. We are grateful for the Lord’s work, for His power guarantees that we will fulfill our role and advance in holiness (Phil. 2:12–13).
Our job is to live out God’s transforming work and “put on the new self,” which means putting His ways into practice. In other words, it is to live in conformity to Christ. Gregory of Nyssa was one of the fourth-century Cappadocian Fathers who helped codify the language of orthodox Trinitarianism. He comments on Ephesians 4:24: “There is but one garment of salvation, namely, Christ. Hence the “new man” created in God’s likeness is none other than Christ. One who has put on Christ has thus put on the new person created in God’s likeness” (Ancient Christian Commentary on Scripture, vol. 8, p. 165; hereafter ACCNT).