Then God said, “Let Us make man in Our image, according to Our likeness; let them have dominion over the fish of the sea, over the birds of the air, and over the cattle, over all the earth and over every creeping thing that creeps on the earth.” So God created man in His own image; in the image of God He created him; male and female He created them. (Genesis 1:26-27)
Niketas Stithatos (d. ca 1090AD) who wrote the biography of St Symeon the New Theologian, discusses humans being in God’s image and likeness by looking at some of the known characteristics of God which can also apply to us humans:
God created us in his image and likeness (cf. Genesis 1:26). We are in his likeness if we possess virtue and understanding; for ‘His virtue covered the heavens, and the earth was full of His understanding‘ (cf. Habakkuk 3: 3). The virtue of God is His justice, holiness and truth: as David says, ‘Thou art just, O Lord, and Thy truth is round about Thee’ (cf. Psalm 89:8 LXX); and again, ‘The Lord is just and holy‘ (cf. Psalm 145:17).
We are also in the likeness of God if we possess uprightness and goodness, for ‘good and upright is the Lord‘ (Psalm 25:8); or if we are conscious of wisdom and spiritual knowledge, for these are within Him and He is called Wisdom and Logos; or if we possess holiness and perfection, since He Himself said, ‘You must be perfect, as your heavenly father is perfect‘ (Matthew 5:48), and, ‘You must be holy, for I am holy‘ (Leviticus 11:44; 1 Peter 1:16); or if we are humble and gentle, for it is written, ‘Learn from Me, for I am gentle and humble in heart, and you will find rest for your souls‘ (Matthew 11:29). (THE PHILOKALIA Vol 4, pp 142-143)