Kveldulf Gundarsson explains in Teutonic Magic:
In the life of the person who follows the old ways of the Teutonic people, there should be nothing unholy, no time at which you shut yourself off from an awareness of the workings of your soul simply because the thing you are doing is not openly magical or religious in its goal. Rather, you should be aware of the presence of the gods in everything. The first, and most important, re-turning of thought back to the ancient ways comes in dealing with the duality of sacred and profane as seen by the modern world. The terms themselves come from Latin roots; rooted in Anglo-Saxon, the words become “holy” and “unholy,” having very different meanings and connotations. Holy comes from a root meaning “healthy, whole,” showing that in the Germanic mind something holy is not cut off from the physical world, but rather is strong in both the earth and the worlds of the soul which are woven into it. Something unholy is not simply mundane or “non-spiritual” in the way that a profane thing is; it is something sick or flawed. To hallow a place or item is not to set it apart from the world- it is not taboo or untouchable in the sense of the Judeo-kristjan (Norse spelling of Christian) “sacred”-rather, it is filled with such a power of holiness as to ward it from any unholy-warped or woe-working-wights.
Sowilo is the wholiness rune.