Genesis 4:18

And to Enoch was born Gaidad; and Gaidad begot Maleleel; and Maleleel begot Mathusala; and Mathusala begot Lamech.

And unto Enoch was born Irad: and Irad begat Mehujael: and Mehujael begat Methusael: and Methusael begat Lamech.

Irad was born to Enoch. Irad became the father of Mehujael. Mehujael became the father of Methushael. Methushael became the father of Lamech.