דברי הימים ב, פרק ל״א, פסוק ז׳

The rhythm of giving to the Temple naturally followed the cycle of the seasons, turning the agricultural harvest into a prolonged period of national generosity. The process of bringing the priestly and Levitical gifts to the Temple spanned the entire summer, aligning perfectly with the farming calendar from the early harvest to the final gathering of crops. The accumulation of these contributions began in the third month, Sivan. During this early stage of the harvest, the people brought their first fruits, laying the groundwork for what would become massive piles of offerings. This steady collection continued throughout the summer until the seventh month, Tishrei. At this point, as the final gathering of the grain came to an end, the people completed the piles by bringing the rest of their tithes and offerings [מלבי״ם, מצודת דוד, ביאור שטיינזלץ].

The primary approach among commentators is that the initial accumulation of the harvest is understood through a metaphor borrowed from the world of construction. Just as laying a solid foundation is the essential first step in building a house, the placement of the very first batch of grain is viewed as the foundation of the piles. This initial act of giving marked the true beginning of their formation, setting the stage for the collections of produce that would steadily grow over the coming months [רש״י, רלב״ג, מצודת דוד].