דברי הימים ב, פרק ד׳, פסוק ב׳

King Solomon constructed a massive water receptacle for the Temple, famously known as the sea. This enormous basin was cast entirely as a single, solid piece using a mold, rather than being shaped by hammering metal into form [מצודת דוד, ביאור שטיינזלץ].

Its dimensions were highly impressive. The basin measured ten cubits across in diameter from one edge to the opposite side [מצודת דוד, ביאור שטיינזלץ]. The inner space was perfectly round, spanning ten by ten cubits, while its depth reached five cubits [רש״י]. A measuring cord wrapped around the outside revealed a total circumference of thirty cubits [מצודת ציון, ביאור שטיינזלץ]. From these exact measurements of a ten-cubit diameter and a thirty-cubit circumference, a fundamental mathematical principle is established: any circle with a circumference of three units will have a diameter of one unit [רש״י, מצודת דוד, רד״ק].

A parallel account of this giant basin appears in the Book of Kings. While there are slight variations between the two records concerning the surrounding decorations and the total volume capacity of the receptacle, these differences are carefully resolved by comparing the texts to form a complete picture [מלבי״ם].