Concise Bible Dictionary:


From Anstey’s Doctrinal Definitions:

When God created man, He said, “Let us make man in our image, after our likeness” (Gen. 1:26). “Image” has to do with man being set in a place of visibly representing God in the creation (1 Cor. 11:7). “Likeness” has to do with man being made morally like God, who is without sin (Gen. 5:1; James 3:9).
When man fell, he ceased to be like God morally. Hence, in his fallen state, man lost his likeness to God. Thereafter he is not said to be “in the likeness of God.” In fact, Adam’s posterity is said to be “in his own likeness” (Gen. 5:3), which implies that Adam passed on to his descendants his sin-nature, which he acquired in the fall (Rom. 5:12; Psa. 51:5). However, even in his fallen state, man is said to be “in the image of God” (Gen. 9:6). The fall did not absolve him of his responsibility to represent God. But sad to say, that image in man has been marred by sin. Man has not represented God properly in the creation.
When Christ came into the world, Scripture says that He was “the image of God” (2 Cor. 4:4; Col. 1:15; Heb. 1:3). He was not “made” in the image of God (as man was)—He was that by virtue of who He was. Thus, He represented God perfectly as the Head of creation. However, Scripture does not say that Christ was “in the likeness of God,” as man was when God made man. The reason for this is that, when Christ walked here, He was not like God, He was God (John 1:1). Scripture does say that in coming into Manhood, Christ was “made in the likeness of men” (Phil. 2:7; Rom. 8:3). This does not mean that Christ took sinful flesh into union with Himself; He was not like man morally. This statement is referring to the Lord being in the likeness of men constitutionally—having a human spirit (John 13:21), a human soul (John 13:27), and a human body (Heb. 10:5). Though a real Man, He was “sin apart” (Heb. 4:15)—that is, without a sin-nature.
The good news is that God in grace has created a new race of men under Christ (2 Cor. 5:17; Eph. 2:10; Rev. 3:14), wherein both likeness and image are regained. Christ’s “many brethren” (believers) in the new race can now exhibit the moral features of God and thus represent God on earth properly (Rom. 8:29; Heb. 2:11). The epistle to the Ephesians focuses on “the likeness of God” being displayed in this new race (Eph. 4:24-32), and the epistle to the Colossians focuses on the fact that the new race is “renewed in knowledge after the image of Him that created him” (Col. 3:10). Thus, the new race under Christ has regained what the old race lost under Adam.