NASHVILLE  President Bush delivered a rousing defense of the wars in Iraq and Afghanistan on Tuesday, mixing faith and foreign policy as he told a group of Christian broadcasters that his policies in the region were predicated on the beliefs that freedom was a God-given right and “every human being bears the image of our maker.”

In a 42-minute speech to the National Religious Broadcasters convention, Mr. Bush called upon European allies to step up their efforts in Afghanistan, and conceded that recent security gains in Iraq “are tenuous, they’re reversible and they’re fragile.” Still, he insisted his troop buildup there is succeeding.

“The decision to remove Saddam Hussein was the right decision early in my presidency,” Mr. Bush said, to a standing ovation. “It is the right decision at this point in my presidency, and it will forever be the right decision.”

The speech, coming a week before the fifth anniversary of the American invasion of Iraq, is the first of three talks on terrorism and war policy that Mr. Bush will give before next month’s Congressional testimony by the top American military commander in Iraq, Gen. David H. Petraeus, and the senior diplomat there, Ambassador Ryan C. Crocker.