HTB Vicar Nicky Gumbel spoke to around 6,000 people at Belfast's Odyssey Arena last night.
He was the main speaker at 'Revival 2012', a Northern Irish initiative to raise the profile of the Alpha course and other evangelistic initiatives in the province.
Worship was led by Robin Mark, one of Ireland's most popular songwriters and worship leaders.
Nicky spoke on the theme 'Can a nation be changed?' and the tragedy of past splits in the church.
He said, 'Truth and unity go together. We need unity to find complete truth because the complete truth is found in Jesus.
'If we are to see the transformation of this nation, we need the power of the Holy Spirit.'