I think you were writing about Christian Witches not Christian Wicca. Christianity and Wicca are two completely different religions. Witchcraft isn't equal to Wicca. Wicca is a religion and not all Wiccan people use Magic(k).
The difference between Wicca and Witchcraft can be summarized simply: Wicca is a religion whereas Witchcraft is a practise. That begs the questions of what is a religion and what is a practise.
A religion is a spiritual belief system, such as Christianity, Islam, or Wicca. It is a series of beliefs, based around observance to or worship of deities and/or spirits. A practise is something that is done, such as prayer, meditation, or magic. Simply put, magic is a practise and Paganism is a religion. Wicca is a subset of Paganism, and magic/spell casting is the main goal of Witchcraft.
It is, of course, possible to practise magic without being a Witch. There are other forms, such as Ceremonial Magic. And magic can also be part of a religionsome argue that prayer is a version of magic, and that the Wiccan Circle is enacted prayer.
The main difference between Wicca and Witchcraft come with the differences in intent. The purpose of Wicca is to honour the Lord and Lady, observe the turns of the Wheel of the Year, and to pay attention to ones spirituality. Wicca is intimately tied to ones relationship with the divine, by whatever faces They choose to show to us. Witchcraft, on the other hand, does not have to involve deities. Instead, it is concerned with the use of spells and herbs to achieve a desired endhealing, love, protection, etc.
Because Witchcraft is a practise and not a religion, it is possible to be a member of just about any religion and also be a Witch. (Of course, different religions have different opinions about the morals of being a Witch, but that is neither here nor there.) The openness of Wiccans and other Pagans toward magic and the unexplained makes it all the more likely that these people will be drawn to Witchcraft. But be aware that not all Wiccans are Witches. Many do not cast spells of any type. Instead, they focus solely on their relationship with the divine and on their quest for spirituality.
Hi Aaron, As others have said, I believe that a more appropriate term to use for what you do is Christian Witchcraft. Witchcraft is a magical practice, including spellwork, which does not require that you be part of any particular religion in order to do it. Wicca, on the other hand, is a Pagan religion with very specific beliefs and practices that are very, very different than what a Christian would believe is right to do. Confusing the two is not uncommon at all when folks are just starting out.
To go back to your original question, many of the spells you'll find in places like SOM include calling upon Pagan Gods or Goddesses for aid. As a Christian, I would think that you would not want to use these spells unless you altered them to remove the part about Gods and Goddesses.
Christians have engaged in magic, including spellwork for centuries. In fact some of the oldest folk magic spells found in both Britain and the US are based on Bible verses. I would say, look to what the Bible teaches you about right or wrong and use that to decide whether you should do a spell or not.