US President Barack Obama has praised the merits of prayer as a chance to learn from mistakes and to gain the courage to stand up for what is right.
In a statement issued for the National Day of Prayer, Obama said: "In times of steady calm and extraordinary change alike, Americans of all walks of life have long turned to prayer to seek refuge, demonstrate gratitude, and discover peace.
"Sustaining us through great uncertainty and moments of sorrow, prayer allows us an outlet for introspection, and for expressing our hopes, desires, and fears. It offers strength in the face of hardship, and redemption when we falter."
The threats of poverty, violence, and war around the world are all too real, he added.
"Our faith and our earnest prayers can be cures for the fear we feel as we confront these realities. Helping us resist despair, paralysis, or cynicism, prayer offers a powerful alternative to pessimism."
He continued: "Through prayer, we often gain the insight to learn from our mistakes, the motivation to always be better, and the courage to stand up for what is right, even when it is not popular."
Speakers at the National Day of Prayer at Capitol Hill event expressed concern about last year's decision by the US Supreme Court to legalise same-sex marriage.
Tony Evans, the popular pastor and broadcaster from Dallas, who was the honorary chair of the event, was among those who urged Christians who oppose gay marriage themselves to come "out of the closet" and speak about their faith-based position, Deseret News reported.
He said the country was facing chaos because of its disregard for God.
He said: "What we are experiencing today is the passive wrath of God. We want him for invocations, we want him in benedictions, as long he stays away from the meetings in between."
Shirley Dobson, chairman of the National Day of Prayer task force, said: "Was it not shocking to the nation when on June 26, 2015, the very definition and meaning of marriage that has endured for 5,000 years in every civilisation on Earth was redefined, weakened and undermined?"
The National Day of Prayer has been observed annually since 1952.
More than 500,000 people tune in to watch the event live each year. It has been observed by more than 33 million people at 630,000 prayer gatherings around the world.
This year it was announced that Anne Graham Lotz, daughter of Dr Billy Graham, will succeed Dobson as the new chairman of the National Day of Prayer Task Force. This is considered particularly appropriate as it was in 1952 that Graham, aged just 32, was invited to speak at the Capitol, which led to the National Day of Prayer being made law.
