On entering their land, the Israelites were commanded to separate a portion of dough from the bread they would bake and set it aside as offering. During worship in the Tabernacle of the wilderness, and subsequently in the Temple of Jerusalem, the priests removed a handful of the dough - called hallah - and placed it on the altar.
The injunction to separate a portion of hallah continued to be observed in later generations, recalling the Temple service. Though not intended specifically for women, it had by Mishnaic times become one of the three duties incumbent upon a Jewish woman, together with ritual immersion at the end of the menstrual cycle and kindling the Sabbath lights. Since it usually befell upon the housewife to bake loaves for the Sabbath, this duty became linked with the precept to separate the hallah. Women would recite a prayer as they separated a portion of dough and then burned it. Today, instead of purchasing readymade hallot, traditionally observant women have revived the practice of baking them at home in order to fulfill the commandment and enjoy its beneficial effects.