20. 辟, read as, and=僻. 罔,—'en-net', i.e. to entrap. 无所不为已,—已, see on par.16.
21. 终身, generally means 'the whole life'. Perhaps we should translate, 'If come years be good, they will all their lives have plenty', i.e. they will in those years lay by a sufficient provision for bad years.
When they thus have been involved in crime, to follow them up and punish them;— this is to entrap the people. How can such a thing as entrapping the people be done under the rule of a benevolent man?