John Gill Bible Commentary

Ye shall offer up a cake of the first of your dough for an heave offering,.... Of the first dough made of the first corn that was threshed, winnowed and ground, they were to make a cake, and offer it an heave offering unto the Lord; the quantity of it is not expressed, but was left to the people's generosity; no stinted measure was fixed by the law; but according to the Scribes, or the traditions of the elders, the quantity of the cake was the twenty fourth part of the first dough that was kneaded; not the forty fourth, as Buxtorf (p) through mistake says; so the Targum of Jonathan,"of the first of your dough, one out of twenty four (i.e. the twenty fourth part of it), ye shall separate a separation for the priests,''with which agrees the Misnah (q), though according to that, if made to sell publicly it was the forty eighth part of it. Some, because Num 15:21 begins and ends with "mem", which numerically signifies "forty", think this is an instruction to a bountiful person to give the fortieth part (r): as ye do the heave offering of the threshing floor, so shall ye heave it; as the two wave loaves and firstfruits of their harvest, Lev 23:16. (p) Synagog. Jud. c. 34. p. 602. (q) Challah, c. 2. sect. 7. so Schulchan Aruch, par. 2. c. 322. so Jarchi & Ben Gersom in loc. (r) Baal Hatturim in loc.