Then say thou, Thus saith the Lord GOD, The city sheddeth blood in the midst of it, that her time may come, and maketh idols against herself to defile herself.
The city sheddeth blood ... that her time may come. Instead of deriving advantage from her bloody sacrifices to idols, she only thereby brought on herself "the time" of her punishment.
Maketh idols against herself - (Proverbs 8:36).