Here is a story from a Chicago Tribune article from 2007:
'In his 1993 memoir "Dreams from My Father," Obama recounts in vivid detail his first meeting with Wright in 1985. The pastor warned the community activist that getting involved with Trinity might turn off other black clergy because of the church’s radical reputation.
When Obama sought his own church community, he felt increasingly at home at Trinity. Before leaving for Harvard Law School in 1988, he responded to one of Wright’s altar calls and declared a personal relationship with Jesus Christ.
Later he would base his 2004 keynote speech to the Democratic National Convention on a Wright sermon called "Audacity to Hope," –also the inspiration for Obama’s second memoir, "The Audacity of Hope."
Though Wright and Obama do not often talk one-on-one often, the senator does check with his pastor before making any bold political moves.
Last fall, Obama approached Wright to broach the possibility of running for president. Wright cautioned Obama not to let politics change him, but he also encouraged Obama, win or lose…'