“Know therefore and see that it is an evil thing and a bitter [thing], that you have forsaken the Lord your God” (Jer. 2:19). Every sin is a forsaking of the Lord our God. If the heart know not, if it consider not, that it is an evil thing and a bitter [thing] – evil in itself, bitter in its effects, fruit, and event – it will never be secured against it.
– John Owen, The Power and Efficacy of Indwelling Sin