Jeremiah 11:8
"Yet they obeyed not, nor inclined their ear, but walked every one in the imagination of their evil heart: therefore I will bring upon them all the words of this covenant, which I commanded them to do; but they did them not."
Israel's biggest downfall was that they followed man's logic and reasonings and not the voice of God. According to Jeremiah 8, from the time that Israel left the land of Egypt to the time of the writing of this chapter, Israel was a nation that oftentimes followed the "imagination of their evil heart." This was magnified in Judges 21:25 when it says, "In those days there was no king in Israel: every man did that which was right in his own eyes." Yet, this dangerous response led to their eventual captivity and judgment of God.