Of course the original reference is to national apostasy, which was aggravated by the national covenant, and avenged by national disasters, which are interpreted and urged by the prophet as God's merciful pleading with men. But the text is true in reference to individuals.
I. The universal indictment.
This is not so much a charge of isolated overt acts, as of departure from God. That departure, itself a sin, is the fountain of all other sins. Every act which is morally wrong is religiously a departure from God; it could not be done, unless heart and will had moved away from their allegiance to Him. So the solemn mystery of right and wrong becomes yet more solemn, when our personal relation to the personal God is brought in.
Then -- consider what this forsaking is-at bottom aversion of will, or rather of the whole nature, from Him.
How strange and awful is that power which a creature possesses of closing his heart against God, and setting up a quasi-independence!
How universal it is-appeal to each man's own consciousness.
II. The special aggravation.
'Thy God ' -- -the original reference is to Israel, whom God had taken for His and to whom He had given Himself as theirs, by His choice from of old, by redemption from Egypt, by covenant, and by centuries of blessings. But the designation is true in regard to God and each of us. It points to the personal relation which we each sustain to Him, and so is a pathetic appeal to affection and gratitude.
III. The bitter fruit.
6 Evil' may express rather the moral character of forsaking God, while 'bitter' expresses rather the consequences of it, which are sorrows.
So the prophet appeals to experience. As the Psalmist confidently invites to 'taste and see that God is good,' so Jeremiah boldly bids the apostates know and see that departing is bitter.
It is so, for it leaves the soul unsatisfied.
It leads to remorse.
It drags after it manifold bitter fruits. 'The wages of sin is death.'
Sin without consequent sorrow is an impossibility if there is a God.
IV. The loving appeal.
The text is not denunciation, but tender, though indignant, pleading, in hope of winning back the wanderers. The prophet has just been pointing to the sorrowful results which necessarily follow on the nation's apostasy, and tells Israel that its own wickedness shall correct it, and then, in the text, he beseeches them not to be blind to the meaning of their miseries, but to let these teach them how sinful and how sorrowful their apostasy is. Men's sorrows are a mystery, but that sinners should not have sorrows were a sadder mystery still. And God pleads with us all not to lose the good of our experiences of the bitterness of sin by our levity or our blindness to their meaning. By His providences, by His Spirit working on us, by the plain teachings and loving pleadings of His word, He is ever striving to open our eyes that we may see Good and Evil, and recognise that all Good is bound up for us with cleaving to God, and all Evil with departing from Him. When we turn our backs on Him we are full front with the deformed figure of Evil; when we turn away from it, we are face to face with Him, and in Him, with all Good.