Republican campaigners hope a video message from Donald Trump's vice-presidential running mate Mike Pence will be aired in thousands of churches on Sunday.

Polls show Trump closing the gap on his opponent Hillary Clinton, though she is still ahead in key states. 

The video shows Pence, who is Governor of Indiana, speaking of his personal faith in Christ and explaining his reasons for standing with Trump for election.

Pence describes himself as "a Christian, a conservative and a Republican, in that order" and says he is honoured to address his hearers as a "fellow believer".

He says he was raised in "a family where faith was important – church on Sunday, grace before dinner – but my faith became my own when I made a personal decision to trust Jesus Christ during the spring of my freshman year in college".

Pence says: "That night my heart was literally broken wide with gratitude and with joy when I came to realise that what happened on the cross in some small measure actually happened for me. And I know all of you in the room share that same passion and that same sense of gratitude for what was done on our behalf.

"Years later, my faith has been tested, relied on more times than I could possibly count. All I know today is that I need Him more than ever, and he's really the centre of my life and the centre of my family's life."

Pence says he believes Trump has "the right leadership and the right vision to make America great again". He stresses Trump's commitment to "appoint justices to the Supreme Court who will uphold our constitution and the rights of the unborn" and to repeal the Johnson Amendment, which bans charities and churches from using their funds for political campaigning – as Pence put it, "threatens tax-exempt organisations and churches with losing their tax status if they speak out on important issues from the pulpit".

He says "voices of faith" have been responsible for key instances of American progress, beginning with the pulpits that "thundered against the tyranny of King George". He also claims churches spoke out against the evils of slavery, though America's largest Protestant denomination the Southern Baptist Convention, was pro-slavery.

Repeating Trump's campaign slogan, Pence says he believes it is "a time in the life of our nation when people who cherish life, when people who cherish our liberties, when people who cherish the great traditions that are enshrined in our constitution should come together and support Donald Trump and our agenda to make America great again".

He cites Lincoln's prayer and urges his hearers to pray "not so much that God would be on our side, but that we would be, in his words, on God's side". He concludes by appropriating 2 Chronicles 7:14 for the campaign, in which God tells Solomon he will "hear from heaven" and heal the land if the people humble themselves and repent.