John Wesley described the Christian life as consisting of "continual warfare." The spiritual struggle involved in faithful living is real, in Wesley's view. It means that we need "every moment" to be watchful and to pray so that we don't fall into the temptations that surround us at every turn. Because the Christian life is a spiritual life, it intersects with the spiritual realm. For Wesley, our own spirits are under the influence of spirits we can't see with our eyes—the Holy Spirit, of course, but also angels and demons that seek to do us either good or ill.

Well known for his "practical divinity," or writings on the practical Christian life, Wesley was also wont to venture into more speculative territory when it came to his writing on spiritual warfare. He was fascinated by the role that angels play in our faith. He believed strongly that we needed to be aware of the danger that Satan and his demons represented to us. Wesley could also become captivated by thoughts on what the "heavenly country" from the book of Hebrews might be like—a restored creation for a redeemed humanity in the kingdom to come. This volume covers all that ground as we have it from Wesley's pen, with twelve sermons on the spiritual life and the spiritual realm that are both practical and speculative in nature.