וְאֶת־בָּתֵּ֥י יְרוּשָׁלִַ֖ם סְפַרְתֶּ֑ם וַתִּתְֿצוּ֙ הַבָּ֣תִּ֔ים לְבַצֵּ֖ר הַחוֹמָֽה׃
And ye numbered the houses of Jerusalem, and ye broke down the houses to fortify the wall;
Rashi on Isaiah
And the houses of Jerusalem you counted how many houses each one had, that they give of them proportionally, to take the stones and the wood to fortify the wall.
Ibn Ezra on Isaiah
And ye have numbered, etc. They had to count the houses, in order to know the number of the soldiers.11It was desirable to know the number of the houses, in order to ascertain how many soldiers the town might be able to keep.
Rashi on Isaiah
to fortify (לְבַצֵּר), to strengthen, an expression similar to “fortified cities” (בְּצוּרוֹת) (Num. 13:28).