Rt Revd John Chalmers once spoke out against the people who only go to services once a year but now says those comments were 'foolish'.
In his annual Christmas message he said had changed his mind.
"Years ago I thought it was the role of a Presbyterian minister to be critical of all the excess materialism which pervaded Christmas," he said.
"So one Christmas Eve in front of packed congregation I had a go at those people who, in my opinion, didn't pay attention to the real meaning of Christmas and I put the tin lid on it by criticising those who only came to church once a year.
"I have repented of such foolishness. Now I believe that those who pack our churches on Christmas Eve do so because the power of Christmas still draws them in to hear the story of God, in the life of a tiny baby, breaking through the darkness to bring light into the world."
It's thought tens of thousands of people will attend churches this Christmas when they normally do not go.
The Moderator added: "If it's got anything to do with me there will be a warm welcome awaiting you and there will be an opportunity for you to put Christ back into Christmas.
"One hundred years ago on the Western Front it was the power of Christmas that punched a hole in the battle between two warring sides.
"Men climbed out of their trenches, shared their tobacco and chocolate cake and kicked a football on a muddy field.
"We may have something of a romantic notion of what happened on Christmas Eve 1914 and there were mixed motives for soldiers and officers lowering their guns and extending the hand of goodwill, peace, love and Christmas cheer, but what else than the heart of Christmas could have made even that temporary pause in hostilities happen.
"Love came down at Christmas and I will continue to pray for a day in the future when goodwill, peace, love and Christmas cheer will breakout across many other hostile fronts."