WASHINGTON -- Members of National City Christian Church are upset after learning their pastor apparently plagiarized sermons he found on the Internet.

The Washington Post reported that the Rev. Alvin O'Neal Jackson acknowledged using sermons from the Rev. Thomas K. Tewell, pastor of Fifth Avenue Presbyterian Church in New York City and the Rev. John Buchanan, pastor of Fourth Presbyterian Church of Chicago, without permission and without giving the men proper credit.

The alleged plagiarism came to light in June when a member of Jackson's congregation searched for the title of a sermon he preached and discovered it had been delivered months prior by Tewell.

Since then, other searches indicate the trail of "borrowed" sermons stretches back at least a year and a half. The newspaper reported that Jackson used Tewell's work in a 12-week series he preached last fall that was boxed and sold for $50.

Jackson said not giving Tewell and Buchanan credit was an error uncharacteristic of his ministry at the flagship congregation of the 800,000-member Christian Church (Disciples of Christ).

"I take full responsibility for what I've done," Jackson said. "It was poor judgment on my part."

He cited a year and a half of "major personal crisis," including back surgery. He said he is "overextended, preaching not only at National City but all over the world."

Jackson came to National City in 1998 as a high-profile minister.  His previous church, Mississippi Boulevard Christian Church in Memphis, grew from 350 members to more than 8,000 in 19 years under his leadership. His salary at 300-member National City is $168,000 a year, excluding benefits.

Tewell, who is on leave from his church and has not heard tapes of Jackson's sermons, told the newspaper Jackson's use of his copyrighted material goes beyond borrowing material from another pastor.

"It seems like he directly plagiarized a lot of material," he said. "My sermons are so personal, it's hard for me to conceive of anyone doing that."

The Rev. William Chris Hobgood, who will complete the term of retiring denomination President Richard Hamm beginning in October, said Jackson could be fired or lose his credentials for ministry if the congregation or denomination decides his actions constitute ministerial misconduct.

The Christian Church is made up of autonomous congregations. Discipline of a pastor ultimately rests in the hands of each congregation.

Hobgood, who is a member of National City, said he knows of only two or three dozen Disciples who have lost standing because of misconduct -- none because of plagiarism --during his 42 years of ministry.

"I'm saddened if the allegations (against Jackson) are proven true," Hobgood said.

Jackson is scheduled to moderate the denomination's biannual meeting in October.