Rock who begot you is a poetic name of God given to Him by Moses. It appears in parallel with another name, the God who gave you birth. Moses was warning the people of Israel how their relationship with God could easily become distant and damaged.
Rock who begot you in Hebrew:
Strong’s Concordance numbers: 6697, 3205
Bible reference: Deut. 32:18
You neglected the Rock who begot you,
And forgot the God who gave you birth. (Deuteronomy 32:18)
Other English versions use different names in this verse: God who made him (MSG) and the Rock who fathered you (NIV).