출애굽기 38:28의 주석

וצפה ראשיהם [HE MADE HOOKS FOR THE COLUMNS] AND OVERLAID THEIR TOPS – the tops of the columns (not of the hooks) with them (the 1775 shekels of silver), for it is said with regard of all of them (the columns of the enclosure as well as of those of the vail at the entrance) (v. 19) “and the overlaying of their chapiters and their fillets were of silver”.

ואת האלף ושבע מאות, and of the one thousand and seven hundred, etc. This refers to the silver not described as having been used to make the sockets. Our sages in Shemot Rabbah 51,5 claim that while Moses was busy enumerating what had been made out of all the gold and silver, etc., he sat down for a moment and forgot what had been made out of these 1775 shekels of silver. When he remembered, the Torah added the letter ו in the word ואת.