Adam and Eve were created in God’s image, after His likeness (Gen. 1:26). But in Adam’s sin, the human race was given over to corruption (Rom. 5:12-21). We are still image-bearers (Gen. 9:6; James 3:9), but the image has been distorted (Gen. 6:5; Eccles. 7:29). The goal of sanctification is the renewal of this image. The holy person is being renewed in knowledge after the image of the Creator (Col. 3:10), which means growing in righteousness and holiness (Eph. 4:24). This does not happen all at once, but rather, we are transformed into the image of God one degree of glory to another (2 Cor. 3:18). God is holy, so most basically being holy means being like God. This is why it’s so critical that Christians know the character and work of the one they worship. If you want to know what holiness looks like, look at God.
Kevin DeYoung