John Gill Commentary Jeremiah 15:6

"Thou hast rejected me, saith Jehovah, thou art gone backward: therefore have I stretched out my hand against thee, and destroyed thee; I am weary with repenting." — Jeremiah 15:6 (ASV)

You have forsaken me, says the Lord
His worship, as the Targum; and had set up idols, and idol worship; and this was the cause of the sword, pestilence, famine, and captivity, and of all the evils that befell them:

You are gone backward ;
from the law of the Lord, and from his pure worship and service, from his ways and from his ordinances; and therefore it was but just they should go into captivity; hence it follows:

Therefore will I stretch out my hand against you, and destroy you ;
his hand of power and vengeance, which when stretched out, and falls with weight, whether on particular persons, or on a nation, brings inevitable ruin and destruction with it:

I am weary with repenting ;
not that the Lord ever changes his mind, or the counsel of his will; in this sense he is without repentance; but the conduct of his providence, and the dispensations of it; not executing the threatenings denounced, but sparing them a little longer, showing mercy, and exercising patience and longsuffering; but now he was as one weary and tired out, and was determined to bear no longer with them, but stir up all his wrath against them, and destroy them.