4 But while the Church finds delightful repose in those who thus sweetly and humbly sit at her feet, here is one who knocks, and says: “What I tell you in darkness, that speak ye in light; and what ye hear in the ear, that preach ye upon the house-tops.” It is His voice, then, that knocks at the gate, and says: “Open to me, my sister, my neighbor, my dove, my perfect one; for my head is filled with dew, and my locks with the drops of the night.” As if He had said, You are at leisure, and the door is closed against me: you are caring for the leisure of the few, and through abounding iniquity the love of many is waxing cold. The night He speaks of is iniquity: but His dew and drops are those who wax cold and fall away, and make the head of Christ to wax cold, that is, the love of God to fail.
For the head of Christ is God. But they are borne on His locks, that is, their presence is tolerated in the visible sacraments; while their senses never take hold of the internal realities. He knocks, therefore, to shake off this quiet from His inactive saints, and cries, “Open to me,” thou who, through my blood, has become “my sister;” through my drawing near, “my neighbor;” through my Spirit, “my dove;” through my word which you have fully learned in your leisure, “my perfect one:” open to me, go and preach me to others. For how shall I get in to those who have shut their door against me, without some one to open? And how shall they hear without a preacher?
Source: Tractates on the Gospel of John (New Advent)