Saint Bonaventure says, “For she was the Virgin, who was closest to him, and therefore accepted his words and reserved them for others.” And further, “she was also the great contemplative. Thus, Bernard says 'Blessed Mary has penetrated the most profound abyss of divine wisdom to a degree that is almost incredible, so that we can say of her that she is immersed in inaccessible light (cf. 1 Tim 6:16) as utterly as is possible to any created nature not deified by hypostatic union.” (Com on Lk, ch. 10, n. 79) (St. Bernard’s Sermon for the Sunday within the Octave of the Assumption of the BVM, 3)
The editors of Bonaventure’s Opera Omnia “rightly indicate that the phrase, “inaccessible light” stems from 1 Timothy 6:16”, says Robert J. Karris, OFM
1 Tim 6:16: “Who only hath immortality, and inhabiteth light inaccessible, whom no man hath seen, nor can see: to whom be honour and empire everlasting. Amen.” Which presents in itself basis that she is rightly called Queen of Heaven and Earth by the Church.