Trump slams 'critics' in his first commencement address as president The president also emphasized the role faith plays in America.

 -- President Trump in a commencement address at Liberty University both went after his critics and emphasized the role faith plays in America.

“The fact is, no one has achieved anything significant without a chorus of critics standing on the sidelines explaining why it can't be done,” Trump told the crowd in Lynchburg, Virginia, in what was his first commencement speech as president. “Nothing is easier or more pathetic than being a critic...The future belongs to the people who follow their heart no matter what the critics say because they truly believe in their vision.”

Liberty is a Christian university founded in 1971 by pastor and conservative activist Jerry Falwell. Following Falwell’s death in 2007, his son, Jerry Falwell Jr., took over as university president. Falwell endorsed Trump’s run for the presidency in January of 2016.

Before Trump’s speech, Falwell in his address commented that Trump’s presidency has benefited the Christian community in the U.S. and presented the president with an honorary Doctorate of Law degree.

Following a tumultuous week that saw the firing of FBI Director James Comey, Trump didn’t waste time taking the opportunity to lay into his critics.

“In my short time in Washington, I have seen firsthand how the system is broken,” Trump told the crowd. “A small group of failed voices who think they know everything and understand everyone want to tell everybody else how to live and what to do and how to think, but you aren't going to let other people tell you what you believe, especially when you know that you are right.”

Trump also touched on the role of faith in America throughout the nearly 30-minute speech, receiving huge applause when announcing, “In America we don't worship government, we worship God.”

“As long as I am your president, no one is ever going to stop you from practicing your faith or from preaching what is in your heart,” he later added.

Trump also took time during the speech to discuss the history of Liberty University and give a nod to its athletics program. He also called out former Buffalo Bills quarterback Jim Kelly, whom he said is a friend and who was in the crowd to watch his daughter graduate.

Trump previously visited Liberty in the midst of his Republican primary campaign in January 2016.

On his way to Lynchburg this morning, Trump spoke briefly on Air Force One during the flight to discuss the timeline of the search for a new FBI director.

"We can make a fast decision," Trump said when asked if there will be a decision before his upcoming foreign trip. When asked if the decision will come before the trip, the president said "even that is possible."

Trump also described the candidates for the post as "outstanding people," "very well known" and of the "highest level."

ABC News' Katherine Faulders contributed to this report.