Justin Bieber's mom, Pattie Mallette, loved on the students at Liberty University by sharing with them her experience of how God won her heart after going through overwhelming circumstances that most people would have lost all hope. Meanwhile, she challenged the students at the largest Christian university in United States to take actions rather than just talk about their intentions.

"We are not made to sit on the sidelines while people suffer. We are commissioned to make great change in this world," she said on Monday at the school's convocation on Sept. 30, according to the school's press release. "Today it is my responsibility and it is your responsibility to step up and make a difference."

Mallette, who raised pop sensation Justin Bieber as a single mom, said people today are discouraged from what she called "you are only" circumstantial statements, preventing them from mustering up the courage to challenge themselves in the fight against injustice and oppression.

She then shared her story, which is detailed in her best-selling book "Nowhere But Up," of how despite overwhelming circumstances in her life, including neglect, abuse, addiction, attempted suicide, poverty, and an unplanned teen pregnancy, God never gave up on her and captured her heart with His love, according to the school's press release.  

Mallette recently launched her foundation, Round 2, which seeks to offer a second chance to those who have been knocked down by providing assistance and resources to those in distress.

She then described the Bible story from 1 Samuel 17 and taught the kids in the stadium pews the lesson from the fight between Israel's greatest king, David, and Philistine's champion, Goliath, who stood at 9 feet tall.

The Israelites came dressed for war every day for 40 days but retreated in fear each time because of the giant Goliath's heckling. When the shepherd boy David came to the battlefield, he too was discouraged by the giant's words, but instead of drawing back, he took action, the university's press reported.

"In spite of the condescending disapproval and the sheer size of the feat ahead of him, something rose up inside (David) against injustice to take action," she said, adding David's words to King Saul, "Let no one lose heart on account of this Philistine, your servant will go out and fight him."

This is what made David different from the rest of the crowd, she said.

"David makes one of the greatest leaps for anyone, in my opinion; he goes from (saying) 'Someone should do something about this' to 'I will be the one to do something about it.'"

"If we are going to be the people who impact every corner of culture, we need to take that leap," Mallette said. "We have to develop the attitude, like David, that says I will do whatever it takes to fight against oppression and injustice." 

On Friday, Duck Dynasty's Willie Robertson was also invited as a guest speaker for the school's convocation events, in which he attributed the source of his family's success to his father, Phil Robertson's decision to accept Christ into his life, and reminded the students that his family considers success not as the world considers but as bringing the Gospel of Jesus Christ to people across the nation.