Why is it that we are so busy with the future? ...Is there not a criminal interference with him to whom it belongs, in our feverish, anxious attempts to dispose of it, and in filling it up with shadows of good and evil shaped by our own wild imaginations? To do God’s will as fast as it is made known to us, to inquire hourly – I had almost said each moment – what he requires of us, and to leave ourselves, our friends, and every interest at his control, with a cheerful trust that the path which he marks out leads to our perfection and to himself, this is at once our duty and happiness; and why will we not walk in the plain, simple way?

Source: Memoir of William Ellery Channing, Vol. 2