“You shall craft the ark with compartments [kinim]” – rooms and dwelling quarters. Rabbi Yitzḥak said: Just as a nest of birds [ken]26The term ken refers to a pair of birds, in this case the two birds used in the purification of the leper (see Leviticus 14:22). purifies the leper, so, too, your ark purifies you.27All the toil that you invest in its construction will purify you of any sins you may have.
“You shall coat it within and without with pitch” – here it says: “You shall coat it [within and without with pitch]…” and elsewhere it says: “She coated it with clay and with pitch” (Exodus 2:3).28Regarding the basket Moses’ mother prepared for him when she placed him in the river. It is because in that case the water current was weak,29So it didn’t require a double layer of pitch. so “she coated it with clay and with pitch” – with clay to block the odor,30The inside layer, of clay, was to block the foul odor of the pitch, of the outer layer. and with pitch to block [penetration of] water.