Blair told the 465 graduates of the private, liberal arts college Sunday to pursue "noble causes" such as helping save millions of people who die in Africa of preventable diseases, the Waterville Morning Sentinel reported.
"Compassion is as important as ambition," Blair said. "So don't just choose a career, choose a cause. There are many to choose from. ... The noble causes -- believe me, they're there amongst all the drudgery and self-obsession of human existence -- find them and save a bit of yourselves for them. It's worth it."
He called on graduates to respond to injustices and said international cooperation is one way to do so.
Blair, whose decade serving as prime minister ended in 2007, reminded the students some people in the United States don't have opportunities Colby graduates have. Those who become leaders, he said, have a responsibility to help others. He cited "sick people who don't get healthcare" as an example.
Police removed three protesters and arrested a Bangor man on charges of disorderly conduct. A few protesters with anti-war signs stood silently for the speech.