Parashas Pekudei · Passuk 40:17
Torah Temimah points to Yerushalmi Shekalim 1:1.
English: From when is the chamber-offering collected? From the first of Nisan, as it says that the Tabernacle was erected on the first of the month; it was taught that on the very day the Tabernacle was erected, the collection was made.
Derash fixing the annual timing of the Temple treasury collection.
The new annual shekalim collection begins on the first of Nisan.