The Gemara states that Rava raises a contradiction: We learned in a mishna (Orla 3:1): A garment that one dyed with dye extracted from peels of orla must be burned. Apparently, the change in appearance precipitated by the orla peels is considered a significant matter, and the dye retains its status as orla. And raise a contradiction from another mishna (Oholot 3:2): With regard to a quarter-log of blood from a corpse that was absorbed in the floor of a house, every vessel in the house is ritually impure by virtue of being under the same roof as the blood. And some say that any vessel in the house is ritually pure. And these two statements do not disagree, as this first statement was in reference to vessels that were in the house at the outset, before the blood was absorbed; and this second statement was in reference to vessels that came into the house at the end, after the blood had already been absorbed.

The mishna continues: If the blood was absorbed in a garment, it is examined, and if the garment is washed and a quarter-log of blood emerges from it, it is ritually impure, and the garment imparts ritual impurity to the vessels in the house as well. But if not, i.e., if less than a quarter-log of blood emerges, then it is pure, and it does not impart impurity. Apparently, only the blood that can be removed from the garment is considered blood, while the blood absorbed in the garment is insignificant. If this is the case, the change in appearance precipitated by the blood is not considered a significant matter, and the blood absorbed in the garment does not remain an independent substance.

The Gemara presents an answer. Rav Kahana said: A halakha from among the leniencies applied to the measurements of a quarter-log was taught here, as the mishna is written in reference to the blood of submission that is discharged from a body at the time of death, and such blood is ritually impure by rabbinic law, but in general, a change in appearance precipitated by blood is significant.

§ Having cited a contradiction raised by Rava, the Gemara proceeds to cite another. Rava raises another contradiction. We learned in a mishna (Shevi’it 7:1): Concerning plants from among the species that are used as dyes, for example the sefiḥin, i.e., produce that grew without being intentionally planted, of woad and safflower; they have sanctity of the Sabbatical Year and money exchanged for them has sanctity of the Sabbatical Year. Additionally, they are subject to the halakha of eradication, and money exchanged for them is subject to the halakha of eradication. Apparently, wood, a type of inedible growth, is subject to the sanctity of the Sabbatical Year despite the fact that it is not edible.

And raise a contradiction from a baraita: With regard to reed leaves and vine leaves that one piled for storage upon the field, if he gathered them for eating, they are subject to the sanctity of the Sabbatical Year; if he gathered them for use as wood, e.g., for kindling a fire, they are not subject to the sanctity of the Sabbatical Year. Apparently, wood or any other non-food product is not subject to the sanctity of the Sabbatical Year.

And Rava answers the contradiction, as the verse states: “And the Sabbath produce of the land shall be for food for you” (Leviticus 25:6), indicating that the sanctity of the Sabbatical Year takes effect only with regard to those items whose benefit and whose consumption coincide, as is the case with regard to food. Wood is excluded, as its benefit follows its consumption. The primary purpose of kindling wood is not accomplished with the burning of the wood; rather, it is with the charcoal that heats the oven. Therefore, wood is not subject to the sanctity of the Sabbatical Year.

The Gemara objects: But isn’t there wood that is used to provide heat, whose benefit coincides with its consumption, as one enjoys the warmth provided by the fire while the wood is burned?

Rava said: