The former Republic of Ireland international confirmed on Monday he was offered the position at Celtic - and insists his decision to turn it down is proof he has not joined Bolton to boost his wage packet.
"I've never been motivated by money in my life," he said. "If it was finance I would have taken the job at Celtic in the summer. That is just a knee-jerk reaction from people that do not know me.
"I have an unbelievable challenge ahead here at this magnificent club, with a magnificent stadium, and I have to take that on.
"You want to be the best you can be and that's my motivation.
"I want to be involved at the highest level and the highest level in world football is the Premier League.
"There's no doubt about it, the best individual players in world football operate in the Premier League. You want to go and compete with the best in the business.
"Celtic were the team I supported as a boy and I spoke with Celtic in the summer.
"They offered me the job and I turned it down to stay at Burnley.
"I think that puts to bed anything about finances."