מלכים א, פרק ז׳, פסוק כ״ג

The construction of the Temple required the creation of massive vessels, and one of the most impressive was an enormous water basin designed for the purification needs of the priests. Known as the Sea, this giant water receptacle [מצודת דוד, ביאור שטיינזלץ] served as a ritual bath where the priests immersed themselves to become pure [רש״י, רלב״ג, אברבנאל]. Because proper immersion requires natural, flowing water rather than drawn water, the basin was not filled manually. Instead, water flowed from an underground spring, rising into the basin through the hollow legs of the oxen that supported it [מצודת דוד, רלב״ג, אברבנאל].

The structure was cast as a single solid piece. Molten metal was poured directly into a mold in the ground, rather than being formed by hammering and joining separate parts together [מצודת דוד, רד״ק, ביאור שטיינזלץ]. The basin formed a perfect circle [רש״י, מצודת דוד]. It measured ten cubits across from one edge to the opposite side, and its depth reached five cubits [רש״י]. A measuring line wrapped around it showed a circumference of thirty cubits [ביאור שטיינזלץ].

These measurements spark a discussion among commentators, since a circle with a ten-cubit diameter should have a circumference slightly larger than thirty cubits. One approach is that the measurements are approximations, relying on a general rule that any circle with a width of one handbreadth has a circumference of three handbreadths [רש״י, מצודת דוד, רד״ק]. Conversely, other commentators offer an explanation that aligns the measurements with greater mathematical precision. They suggest that while the ten-cubit diameter was measured from the outer rim, the thirty-cubit circumference was measured along the inner space of the basin. By calculating the thickness of the basin walls, which was one handbreadth, and subtracting it from the overall outer diameter, the ratio between the inner diameter and the inner circumference becomes highly accurate [מלבי״ם, רלב״ג, אברבנאל].