Heh, well, horror is the style, but the piece is a fragment. The 'context' would be the framework that answers questions like, what is the significance of the tissue, the difference between moral and material danger, the 'mystical words', why they made your heart tremble, the importance of the date, the 16th of March, and why three days? That would be the 19th of March. Why is that significant? This is nice work, but it reads like a paragraph ripped from a novel without anything that a reader can actually understand.
The concept is great, but there are so many questions left unanswered. This should be expanded into a short story, at the very least. You are off to a good start, but the reader needs to know the answers to the questions you raise.

I would suggest that you work on this one, go back and find a 'beginning', and keep it all in this thread. The writing needs a start, and a finish. Just keep at it. If it's all in one thread, it's easier for other readers to find.