Members at New Life Church are not quick to question God's authority, said one young worshiper. So when a gunman dawns on the church campus and causes the death of two teenage sisters before being shot down by a church security guard, the church is not angry or in despair and asking God "why?"

"God didn't do this. That was Satan attacking," Savannah Miller, 14, of New Life told The Los Angeles Times.

Rather than questioning God, New Life members are turning to God during this tragic time. Moreover, they're celebrating the miracle of that fateful day.

"God protected so many people here that day," said Miller.

On Sunday afternoon, 24-year-old Matthew Murray shot and killed Stephanie Works, 18, and her sister Rachel, 16, at the parking lot of New Life Church in Colorado Springs. Twelve hours earlier, the gunman killed Tiffany Johnson, 26, and Philip Crouse, 24, at Youth With a Mission training centre in Arvada.

Police in Colorado Springs believe the gunman intended to gun down many more victims at the megachurch before he was shot down by Jeanne Assam, a volunteer security guard, just as he entered the church building. He was carrying an assault rifle, two handguns and as many as 1,000 rounds of ammunition. An autopsy confirmed that the gunman died of a self-inflicted wound.

New Life members called it a miracle that hundreds of lives were saved that day.

The shooting took place just a year after church founder and then senior pastor the Rev Ted Haggard was fired. A male prostitute had alleged Haggard paid him for sex and methamphetamine. Haggard confessed to "sexual immorality".

While attendance at the church has declined since the scandal, the prominent megachurch had set itself on a new course of recovery with new senior pastor Brady Boyd and 10,000 members before the tragic shooting.

"The devil has been really trying to break down our church," said Tanner Vanbebber, 15, of New Life to The LA Times. "But I think we're going to come up even stronger."

"This is building our faith," said Chris Gordon, 16. "We must be doing something right in this church if Satan doesn't like it."

"The question 'Why did God let this happen?' is a stupid one," said Hayden Trobee, 15. "One of the cool things about New Life is, we're not quick to question God's authority."

On Wednesday, the church was packed with families and teens who said they had laid down their anger, fear and questions, to focus on worship.

Survivors at Youth With a Mission (YWAM) in Arvada are also moving past the tragedy and placing trust in God.

"Lord, we don't know why two of our dear friends died in this hallway. But although we don't understand why, we trust you," prayed Peter Warren, director of the Denver chapter of Youth With a Mission.

Just days after the shooting, students and leaders at the missionary training centre shouted a message to the gunman: "I forgive you, Matthew!"

"The enemy has been defeated and death couldn't hold You down. We're gonna lift our voice in victory, we're gonna make Your praises loud," the students sang on Tuesday. They rededicated the dorm building, where the shooting took place, to God.

Speaking for the first time since the shooting, Charlie Blanch, 22, who was shot in the leg at the centre, said on Wednesday, "In the midst of this, I know that God is good. And He's helped my legs heal. I wholeheartedly forgive Matthew Murray, and my prayers go out to his family," according to Rocky Mountain News.

The families of the two YWAM victims have also offered Murray and his family forgiveness.