For precept [must be] upon precept, precept upon precept,.... Signifying, that they must be dealt with as children were, when first instructed in the rudiments of a language, first had one rule given them, and then another, and so one after another till they had gone through the whole:
line upon line, line upon line; who are taught first to write one line, and then another; or to draw one line, and write after that, and then another; or where to begin one line, and, when finished, where to begin another; for the allusion is to writing by line, and not to a line used in building, as Kimchi and Ben Melech think:
here a little, [and] there a little; a small lesson out of one book, and a small lesson out of another; a little one day, and a little on the next, and so on, that their memories may not be overburdened.