The Gemara in Bava Metzi'a (42a) says that you make a bracha before counting your grain, because (according to R' Dessler in Michtav Me'eliyahu at the beginning of his piece on Neis vs. Teva) Hashem might add grain without you noticing - a Neis Nistar.*
The Ritva, in line with R' Dessler's p'shat (or rather, the p'shat that R' Dessler would later say), applies to that Gemara this passuk in Malachi, suggesting that it's quite literally opening the storehouses of Heaven to pour out grain - enough to be noticeable had you counted but not enough to be noticeable now that you haven't. (The passuk, which concluded that there would be so much grain that there wouldn't be anywhere to put it all - "and I will throw down upon you blessing without end" - would then be referring to times in which Hashem did act with a Neis nigleh.)
*The other explanation we gave in shiur - I forget who it was who said this - was that it's to avoid an ayin hara. It's unclear to me whether this opinion would agree to this understanding of the passuk and simply decided to explain the Gemara differently.