Both in the continuation and removal of comfort the Spirit acts arbitrarily. No man can say how long he shall walk in this pleasant light, Psalm. 30:7. "By thy favor thou hast made my mountain stand strong, thou hidest thy face, and I was troubled." And when in darkness, none can say how long it will be ere that sweet light break forth again. God can scatter the cloud unexpectedly in a moment, Cant. 3:4. "It was but a little that I passed from them, but I found him whom my soul loveth." There is such an observable difference in David's spirit in some Psalms, as if one man had written the beginning and another the end of them.