She also told the story of Immaculee Ilibagiza, a Rwandan genocide survivor who hid for three months in a small bathroom as most of her family members were killed.
Instead of becoming bitter and resentful from what she had experienced, Ilibagiza allowed her relationship with God to grow in a profound way and eventually wrote a book about how her Catholic faith allowed her to forgive her family's killers.
Monahan said that this "beautiful story of forgiveness" provides a model for all those struggling with the temptation to cling to anger against the sins of others.
She also told stories from her own life of being ridiculed and belittled by federal government coworkers for her beliefs on abstinence and how she tried to respond with prayer, love and invitations to dialogue.
An important part of being able to witness is a solid prayer life, which helps us "to talk with God, to have a relationship with him," Monahan said, describing how she discovered "the adventure that it was to grow in a relationship with our Lord."
Prayer also gives us strength in tough moments "to have incredible strength to do things that we never expected to be able to do," she added, noting that sometimes we are "just given words to say" in a difficult situation.
She pointed to the example of Jesus during his agony in the garden, observing that "before he was about to go into a very hostile environment on Calvary, he spent time in prayer."
Sometimes we are given the strength to just stand firm as a loving presence in a hostile environment, and this can plant seeds, Monahan said.
When we are overwhelmed and tempted to give up, we should keep in mind that "we're just showing up and letting God do the work," she emphasized.
This is important to remember, particularly when we feel inadequate, because if we allow ourselves to be instruments, "the grace of God really comes through," she stated.