Complex sentence: Jael promised to hide Sisera and covered him with a rug; but after he fell asleep, Jael drove a tent peg through his temple with a mallet, her blow being so forceful that the peg pinned his head to the ground.
Split into simpler sentences: Jael promised to hide Sisera and covered him with a rug, but after he fell asleep, Jael drove a tent peg through his temple with a mallet. The blow was so forceful that the peg pinned his head to the ground.