Shabbos, Mishnah 7. The Mishnah continues to discuss the required size of a cheres - a shard of an earthenware vessel - the minimum size at which the shard is still considered a usable item, and on this the Tannaim disagree.
Three opinions regarding the size of the shard:
Rabbi Yehudah: Its size is enough to be placed between one beam and another. When large wooden beams were laid one on top of another and a gap remained between them, the practice was to insert pieces of earthenware in the gap to keep the wood from warping. That is the use by which the size is determined.
Rabbi Meir: Its size is enough to scoop up fire with it - large enough to serve as a shovel for glowing coals.
Rabbi Yosei: Its size is enough to hold a quarter of a log of liquid or water.
The proof from the verse:
Rabbi Meir seeks support for his position, that it is enough that one be able to scoop up a coal with it. Although this is not an absolute proof, there is a hint to it from the verse that speaks of a prophecy of destruction, that people will not have even small shards of earthenware left in their hands: "Lo yimatzei bein shevarav... shever sheyihyeh bo kedei lachtos mimakom saruf" - "there will not be found among its fragments... a shard with which to scoop [embers] from a place of burning." Evidently, a functional piece of earthenware is defined by the fact that one can scoop up coals with it.
Rabbi Yosei, who held that a receptacle holding a quarter of a log is enough, answered him: is that really a proof? That very same verse goes on to say "velachsof mayim migeve" - "and to skim water from a cistern" - and from here we see that the function of a shard can also be to receive water and hold it. And since the standard quantity of water is a quarter of a log, this is a proof of exactly equal weight for his own position, that the size of an earthenware shard is enough to hold a quarter of a log of water.
In summary: In this Mishnah the Tannaim disagree about the required size of an earthenware shard: Rabbi Yehudah took the measure of being placed between one beam and another, Rabbi Meir the measure of scooping up coals, and Rabbi Yosei the measure of holding a quarter of a log. The latter two Tannaim relied on that very same verse - Rabbi Meir on its opening words ("lachtos") and Rabbi Yosei on its closing words ("lachsof mayim migeve") - each as a hint to his own position.