Knocking can be a message that something outside needs to be inside. This can portray how you project a sense of being a victim on events - when the issue might relate to your attitude. It is a classic symbol of sex as the idea of ‘getting knocked up’ or pregnant - but again, the knock portrays passion that feels beyond your control. The knock at the door can draw your attention to the need to ‘open up’ to discover something you are not facing. See also Door and Houses and Buildings.