therefore, God very pressingly requires this: Jer. iv. 14. 0 Jerusalem, wash thy heart from wickedness....how long shall vain thoughts lodge within thee?

And, let me add, that, unless we make this our chief care; unless we do most solicitously observe this Last Commandment, all our care in observing the former will be utterly in vain; not only in respect of our acceptance and reward with God, but as to any good issue and effect. All other endeavours will be as successless, as to attempt the cure of an ulcerous body, without purging it; where the corruption will quickly break forth again: or to attempt the emptying of a pond, that hath many springs still rising up in the bottom of it; which will soon grow as full as ever it was.