“Staph infection!” The diagnosis hit me hard. The inflamed, hard, puss-filled boil glowing on my child’s leg was even worse than I’d imagined. The repulsive visible damage only masked a more insidious infection evidenced by ominous red streaks radiating from the wound. All efforts to treat the wound topically had been relatively futile as long as the infection raged deep under the skin.
Resentment functions like a staph infection in the soul. It is highly contagious and once contracted is difficult to eliminate, especially by superficial efforts. The germs of resentment, typically born out of genuine or perceived wrongs against me or someone I care about, defile everything they touch. Commonly, the wrong consists either of my having received some form of treatment I don’t feel I deserved or my not having received something I felt I justly deserved.
Unresolved, festering wrongs attach themselves like parasites to the mind and occupy more and more of its energies. The infection can spread in any direction – contempt for those I perceive as beneath me, anger toward my peers, or bitterness toward my superiors. Astoundingly powerful, it can penetrate my spirit and distort my view of God. Often it simmers under the surface long before it flames into painful, more obvious symptoms. Paul Tripp offers an astute observation:
“Harboring bitterness against people is confessing their sin to myself, over and over again. Anger is akin to confessing their sin to God, dissatisfied that he hasn’t done something and placing myself in his position as judge. Gossip is confessing their sin to someone else.” 
One of the many dangers of resentment is that it masquerades for a long time under the guise of righteousness. “After all,” I ask, “Wasn’t wrong done?” “To be quick to forgive might suggest I’m not taking sin seriously.” “Isn’t it right for me to have an offended sense of justice? And to desire at least a little of God’s punishment of the individual? Maybe God will even let me help!”
How does one begin to recognize the defiling infection of resentment, contain its toxic spread, and eradicate its stubborn root?
- When past hurts against me cycle through my mind repeatedly, I’m in danger of developing bitterness.
- When I find myself refusing to see or even look for the hand of God in what transpired, I’m in danger of bitterness.
- When I find myself despising another person and eager to criticize them, gossip about them, and/or avoid them, I’m evidencing a root of bitterness has taken hold.
- When I find myself gripped by other sins like anger, revenge, hate, I’m likely in an early or an advanced stage of bitterness.
- When I find spiritual power for obedience to Scriptural directives toward others – like being kind, loving, forgiving, etc. – neutralized in me, I’m likely in the clutches of resentment.
Recovery from resentment begins not with another’s repentance, but with my own. Am I willing to concede that I allowed another person’s actions to justify my own sin against God? Am I willing to acknowledge that God’s gracious actions toward me in Christ call me to a forgiving response radically opposed to resentment (Ephesians 4:32)? Am I willing to acknowledge that putting resentment away is consistent with what Paul calls “learning Christ” (Ephesians 4:20)? Can I trust God to transform what another may have intended for evil into good (Genesis 50:20)?
My sense of offended “justice” often rationalizes my bitterness. Amazingly, God’s sense of justice constrains Him to forgive (1 John 1:9), and when He does, the blood of Jesus Christ His Son is able to cleanse me from the kind of sinfulness that produces destructive sins like resentment. When I learn to forgive the transgressions of others instead of being embittered by them, I become more like God (Exodus 34:7). Forgiving others requires faith – faith not only in what God has already done for me in Christ, but what He may yet do to triumph where sin once abounded.
Thankfully, the Lord used antibiotics to combat and eradicate my child’s dangerous staph infection. The Great Physician alone can extricate resentment at its root, and an indispensable component of His prescription requires forgiveness:
14 For if you forgive others for their transgressions, your heavenly Father will also forgive you.
15 But if you do not forgive others, then your Father will not forgive your transgressions (Matthew 6:14-15, NASB).
 Paul David Tripp, Instruments in the Redeemer’s Hands, 229, original emphasis