Kabbalah к Шир ха-ширим 1:6

The fourth day, which is the kingdom of David, was rejected by the builders, as it is written: "The stone which the builders rejected..." (Tehilim 118:22) and also "my mother's children were angry with me" (Shir Hashirim 1:6). For this light, (referring to Malchut) lowered itself and diminished its own radiance while the Kelipot were established in their places. This gave place to the emerging of the Kelipot and their rule. Thus she seemed loathsome in the eyes of the righteous that built it. Only later, when she was completed and ready for union with Zeir Anpin, was it said she "has become the head stone of the corner" (Tehilim 118:22). All those lights that shone during the 6,000 year period were suspended in this firmament of heaven to establish with them the throne of David, namely, the kingdom (Malchut) of David.