Shviras HaKeilim, or the Shattering of the “Vessels,” refers to the shattering of the vessels of Tohu, chaos. Before the state of being we are in now, namely all of Hishtalshelus, there was (and because it transcends time, it still is) the world of chaos. In Tohu, everything exists in extremes; chessed exists as a polar opposite to g’vura and so forth. The issue with is they can’t exist at all. The reason is the “light,” or energy pumped into the “vessels” there is beyond the vessels’ capacity causing an “explosion,” so to speak. The broken pieces of Tohu “fell” into what would become the world of Tikkun. Comparable to electricity; the higher the voltage, the more dense the rubber insulation needs to be. The coarsest vessels would fall the “lowest,” or rather, because they are the coarsest, they are the “lowest.” The greatest and most powerful “lights,” or G-dly energy would be compatible and able to integrate with only the coarsest or most “insulating materials.” The same applies to the most delicate vessels and lights.