{Should sleep and rise} (katheud(8869) kai egeir(8874)ai). Present
subjunctive for continued action. So also {spring up and grow}
(last(8369) kai m(886b)un(8874)ai) two late verbs. The process of growth
goes on all night and all day (
ukta kai h(886d)eran, accusative of
time). {He knoweth not how} (h(9373) ouk oiden autos). Note
position of h(9373) (beginning) and autos (end) of clause: {How
knows not he}. The mystery of growth still puzzles farmers and
scientists of today with all our modern knowledge. But nature's
secret processes do not fail to operate because we are ignorant.
This secret and mysterious growth of the kingdom in the heart and
life is the point of this beautiful parable given only by Mark.
"When man has done his part, the actual process of growth is
beyond his reach or comprehension" (Swete).