John Gill Commentary Ezra 4:21

"Make ye now a decree to cause these men to cease, and that this city be not builded, until a decree shall be made by me." — Ezra 4:21 (ASV)

Give you now commandment to cause these men to cease
From building:

and that this city be not builded until another commandment shall be
given from me ;

He might suspect that this case, in all its circumstances, was not truly stated, and that hereafter he might see reason to recede from the present orders he gave.

And the rather, as by searching, and perhaps on his own knowledge, he must have observed, that his father Cyrus had shown favour to the Jews, and had not only set them at liberty, but had encouraged them to rebuild their temple.

Which might be what they were about, and was the case, and nothing else, except their houses to dwell in.