For thus; literally, for therefore; i.e. because he is left in impunity (camp. the use of the phrase in Jeremiah 29:28). He weakeneth the hands of the men of war; i.e. he dispirits them. It is important to get this "outside view" of the preaching of Jeremiah.
There is evidently some excuse for the opponents of Jeremiah. It was a matter of life and death to resist the Chaldeans, and Jeremiah was, according to the politicians, playing into the hands of the enemy (see further in general Introduction).
The addition of the words, that remain, shows that the bitter end of the resistance was fast approaching.