Jer 15:6 You have rejected me, declares the LORD; you keep going backward, so I have stretched out my hand against you and destroyed you— I am weary of relenting.
Jeremiah 15:6 portrays a sense of exasperation. The scene is that, like much of the Bible, God is preparing to judge Israel. This time God will carry through without showing mercy, because He is “weary” of “repenting”. He has been burned by leniency in the past. He has repented but Israel has not taken note and reformed in the long term. Jeremiah is an answer to this continual disappointment. This time is different. This time God will not listen to their pleas.
Not only does this verse show that God’s vision of the future is continuously thwarted by failed expectations in man, but it shows that these failed expectations are taking an emotional toll on God. God is not immutable, impassible, nor does He know the future in any exhaustive sense.