This morning I was reading Alma Chapter 36. Alma the Younger is relating his conversion experience to his son Helaman. In verse 12 he says
15 After I had retired to the place where I had previously designed to go, having looked around me, and finding myself alone, I kneeled down and began to offer up the desires of my heart to God. I had scarcely done so, when immediately I was seized upon by some power which entirely overcame me, and had such an astonishing influence over me as to bind my tongue so that I could not speak. Thick darkness gathered around me, and it seemed to me for a time as if I were doomed to sudden destruction.