Check out this thought provoking quote from Stephen Charnock.  No one has ever brought to my attention the seriousness with which God demonstrates His holiness to those who are His own.

He doth not hate it [sin] in one, and indulge it [sin] in another, but loathes it wherever he finds it; not one worker of iniquity is exempt from it (Psalm 5:5): “Thou hatest all workers of iniquity.” For it is not sin, as in this or that person, or as great or little; but sin, as sin is the object of his hatred; and, therefore, let the person be never so great, and have particular characters of his image upon him, it secures him not from God’s hatred of any evil action he shall commit.

He is a jealous God, jealous of his glory (Exod. 20:5); a metaphor, taken from jealous husbands, who will not endure the least adultery in their wives, nor God the least defection of man from his law. Every act of sin is a spiritual adultery, denying God to be the chief good, and giving that prerogative by that act to some vile thing. He loves it no more in his own people than he doth in his enemies; he frees them not from his rod, the testimony of his loathing their crimes: whosoever sows iniquity, shall reap affliction. It might be thought that he affected their dross, if he did not refine them, and loved their filth, if he did not cleanse them; because of his detestation of their sin, he will not spare them from the furnace, though because of love to their persons in Christ, he will exempt them from Tophet.

How did the sword ever and anon drop down upon David’s family, after his unworthy dealing in Uriah’s case, and cut off ever and anon some of the branches of it? He doth sometimes punish it more severely in this life in his own people, than in others. Upon Jonah’s disobedience a storm pursues him, and a whale devours him, while the profane world lived in their lusts without control. Moses, for one act of unbelief, is excluded from Canaan, when greater sinners attained that happiness. It is not a light punishment, but a vengeance he takes on their inventions (Psalm 99:8), to manifest that he hates sin as sin, and not because the worst persons commit it.

Perhaps, had a profane man touched the ark, the hand of God had not so suddenly reached him; but when Uzzah, a man zealous for him, as may be supposed by his care for the support of the tottering ark, would step out of his place, he strikes him down for his disobedient action, by the side of the ark, which he would indirectly (as not being a Levite) sustain (2 Sam. 6:7). Nor did our Saviour so sharply reprove the Pharisees, and turn so short from them as he did from Peter, when he gave a carnal advice, and contrary to that wherein was to be the greatest manifestation of God’s holiness, viz. the death of Christ (Matt. 16:23). He calls him Satan, a name sharper than the title of the devil’s children wherewith he marked the Pharisees, and given (besides him) to none but Judas, who made a profession of love to him, and was outwardly ranked in the number of his disciples.

A gardener hates a weed the more for being in the bed with the most precious flowers. God’s hatred is universally fixed against sin, and he hates it as much in those whose persons shall not fall under his eternal anger, as being secured in the arms of a Redeemer, by whom the guilt is wiped off, and the filth shall be totally washed away: though he hates their sin, and cannot but hate it, yet he loves their persons, as being united as members to the Mediator and mystical Head. A man may love a gangrened member, because it is a member of his own body, or a member of a dear relation, but he loathes the gangrene in it more than in those wherein he is not so much concerned.

Though God’s hatred of believers’ persons is removed by faith in the satisfactory death of Jesus Christ, yet his antipathy against sin was not taken away by that blood; nay, it was impossible it should. It was never designed, nor had it any capacity to alter the unchangeable nature of God, but to manifest the unspottedness of his will, and his eternal aversion to anything that was contrary to the purity of his Being, and the righteousness of his laws.

~ Charnock, Existence and Attributes of God, Vol. 2, p. 120 – 121