The 7th house, ruled by Libra, relates to relationships of both a business and personal nature. The 7th house determines your experiences with marriage and partnership. Ironically, this area that represents your marriage also holds your open enemies.
On a spiritual growth level, the people with whom you share, whether in love, business, or war, are all here to help you open to a greater level of your spirit. An enemy can perhaps be viewed as a soul who has agreed to help you grow, much the same as a marriage partner.
People want different things in a marriage, and the sign on your Descendant (the name for the seventh house cusp) describes your desires. An Aries Descendant may like fiery passion in a marriage partner, while an Aquarius cusp may need someone who is as much a friend as a partner.
Planets in the 7th house greatly influence the needs of committed partnership. The Moon in the 7th house, for example, may show a strong need for emotional connection, or indicate that the desire for partnership may ebb and flow. If you have Saturn in the 7th house, you probably experience rocky relationships, and do well with a mature partner.
The main point of the 7th house is that you are being called to step away from purely self-serving needs in order to share and cooperate with others. The 7th house is what calls you outside yourself.