These verses show the structure of the entire chapter. We first read how old a certain person was when he fathered his first son. Then we see how long he lived after this, and then total age is mentioned.
It is striking in Genesis 5:3 that Seth is said to be a man in the likeness, in the image of Adam. We see in this a clear reference to Adam being created in God’s image and likeness. Even after the fall, man was still unique and bore the responsibility of conducting himself as God’s image. That remains the command. It is also clear that after the fall, man is still held responsible as being made in God’s image. In the New Testament we read about this in James 3:8–10: No human being can tame the tongue. It is a restless evil, full of deadly poison. With it we bless our Lord and Father, and with it we curse people who are made in the likeness of God. From the same mouth come blessing and cursing. My brothers, these things ought not to be so.
3 When Adam had lived 130 years, he fathered a son in his own likeness, after his image, and named him Seth.