Genesis 1:26
25 God made the wild animals according to their kinds, the cattle according to their kinds, and all the creatures that creep along the ground according to their kinds. God saw that it was good. 26 Then God said, “Let us make humankind in our image, after our likeness, so they may rule over the fish of the sea and the birds of the air, over the cattle, and over all the earth, and over all the creatures that move on the earth.” 27 God created humankind in his own image, in the image of God he created them, male and female he created them.
Genesis 5:3
1 This is the record of the family line of Adam. When God created humankind, he made them in the likeness of God. 2 He created them male and female; when they were created, he blessed them and named them “humankind.” 3 When Adam had lived 130 years he fathered a son in his own likeness, according to his image, and he named him Seth. 4 The length of time Adam lived after he became the father of Seth was 800 years; during this time he had other sons and daughters.
Notes and References
"... The first man's similarity to his son is described with the same two nouns that are used to describe the first two humans' similarity to God (1:26-27). It certainly sounds as if it means something physical here. We surely would have taken it that way if we had read this verse without having read Genesis 1. Still, we must be cautious on such a classic biblical question. In any case, the significance of this verse is to establish that whatever it is that the first humans acquire from God, it is something that passes by heredity. It is not only the first two humans but the entire species that bears God's image ..."
Friedman, Richard Elliott Commentary on the Torah: With a New English Translation (p. 200) Harper Collins, 2003