Sometimes the simplest words in the world are the most challenging. Take the line from the Lord’s Prayer, “Forgive us our trespasses as we forgive those who trespass against us.”

Many Christians say this prayer daily, and then find themselves out in traffic yelling at other drivers within the confines of their cars. They never for one second think that the guy creeping along at 20 miles per hour could be anxiously searching for a parking space, so he can get to his doctor’s appointment.

“The gas pedal is on the right,” we growl through gritted teeth, as we clench the steering wheel and drive past him. Forgive him? That’s the furthest thing from our minds.

Someone sends out a group e-mail including a joke they think is incredibly funny, but we find it offensive, so when we next see them, we duck out of sight to avoid saying hello.

Some family members get into feuds because their political beliefs clash, while neighbors shun each other because of messages displayed on their lawn signs.

At church, we may develop a grudge against a minister whose sermons annoy us, so instead of shaking his hand on the way out, we busy ourselves with picking up the weekly bulletin.

“Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you,” said Jesus, who put the words into action as he died.

The first Christian martyr, Stephen, cried out, as he was being stoned to death: “Lord, do not hold this sin against them.”

Some Christians today practice Jesus’ radical forgiveness, such as the Amish community in Lancaster, Pa., who forgave the shooter who killed five children and injured others, and also befriended the man’s mother.

In Egypt, a Coptic Christian woman lost her husband in a suicide-bombing attack at her church, and responded: “May God forgive you and we also forgive you.”

Some of us are carrying around big grudges that are so old they have cobwebs on them. Often, grudges are passed down to the next generation, so children learn to hate the same people their parents scorned.

The Rev. Martin Luther King Jr., who preached Christ’s path of radical forgiveness, said, “He who is devoid of the power to forgive is devoid of the power to love.”

Children watch carefully the examples set by the grown-ups, so in homes where mom and dad are constantly bickering and under-cutting each other — and refusing to forgive each other — the children follow suit.

And if mom and dad recite the Lord’s Prayer aloud at church, the child gets an additional lesson in hypocrisy.

Sometimes the person we’re called to forgive is staring back at us in the mirror. How many of us beat ourselves up for a sin committed decades ago? We believe God has forgiven us, but extending mercy to ourselves can be a huge challenge.

Instead, we wallow in the “I should haves,” as in, “I should have realized my marriage was in trouble” and “I should have seen the signs of addiction in my child.”

But we’re not omniscient, so we may miss the symptoms of a broken relationship or a troubled heart. Later, of course, it all seems blatantly obvious and can become another reason to blame ourselves.

Learning forgiveness starts with ordinary wrongs like being cut off in traffic, being fired from a job, being left by a spouse. We can respond with bitterness and revenge, which can give rise to a cycle of anger and violence, or practice forgiveness and mercy.

Let’s pray to live by the words of Christ: “Be merciful as your heavenly Father is merciful.” It doesn’t get much clearer than that.