Tamid, Chapter 5, Mishnah 4. Our chapter has been following the kohanim through the morning avodah after the tamid offering, and now it turns to the ketoret: not to the incense itself, but to the vessels in which it was carried into the Heichal.
Two separate utensils were involved, and understanding why there were two is the heart of this mishnah.
Two vessels, one problem
The ketoret was placed in a small spoon, and it was not merely filled but piled high, heaped up past the rim. Serving Hashem with a measure that overflows is an expression of generosity and beauty in the avodah. But that very abundance created a difficulty: as the kohen walked, spices were liable to spill, and letting the ketoret drop onto the floor would be a disgrace to the offering.
The solution was a second, larger vessel, a ladle held beneath the spoon to catch anything that fell along the way. Why not simply carry the ketoret in the large ladle to begin with? Because then the measure would sit low inside it and lose its heaped, overflowing appearance. So the two vessels worked together: the small spoon held the generous, brimming measure of ketoret, and the large ladle underneath guarded whatever escaped.
The words of the mishnah
"Mi shezachah baketoret hayah notel et hakaf." The kohen who had won the lottery for the ketoret would take up the ladle.
"Vehakaf domah letarkav gadol shel zahav, machazik sheloshah kabim." This ladle resembled a large tarkav, a vessel of considerable volume, and it was made of gold. Its capacity was three kabim, so it could indeed hold a great deal.
"Vehabazach hayah betocho, male vegadush ketoret." Inside the ladle sat the bazach, the small spoon, and it was full and heaped with ketoret.
"Vechisui hayah lo." The spoon had a cover. Its purpose was to keep foreign matter from falling into the incense as it was carried to the Heichal, since anything mixing into the ketoret would render it unfit.
"Uchemin metutelet hayah alav milemalah." On top of the cover there was a kind of ring, which served as a handle so that the cover could be lifted off the spoon.