In the two-word linchpin construction of Genesis 3:16a, the word “sorrowful-toil” proleptically anticipates the reference to the same word in 3:17 where God actually curses the ground because of the man and explains its impact in terms of “sorrowful-toil.”
The other word – “conception” – points back to the prior mention of her “offspring” or “seed” in 3:15. This Promise completes the full statement of the Good News, commonly called the “protevangelium.”
