"I'm not a farmer," he explained, to laughter.
Eight years an auxiliary bishop of the New York archdiocese, where he was vicar for administration, Sullivan, 67, succeeds Bishop Joseph Galante, who retired due to ill health.
Galante, who had asked the Vatican last year to be relieved of his duties because of fatigue due to diabetes and kidney failure, sat through most of the lengthy Mass and did not join in the processional or recessional.
"My brother Dennis, I can't tell you how welcome you are from my perspective," Galante, 74, joked in his remarks. "As [the comic character] Jose Jimenez used to say, 'It's not my job.' "
"Farewell, Bishop Joe," said Sullivan, thanking Galante for his nearly nine years as head of the six-county diocese, which counts about 475,000 members.
Noting in his homily that it was "Fat Tuesday," the day before Ash Wednesday and the solemn season of Lent, Sullivan called for "a final fling to let the alleluia ring."
His homily was mostly a litany of praise, punctuated by frequent "alleluias" for his new diocese, which this year celebrates its 75th anniversary.
"To the people of God, who are the church - alleluia," he cried in a booming voice. "To all the priests, now my brothers: I follow in your footsteps. Alleluia."
He also praised Pope Benedict XVI for his "courage and love of the church." Benedict, one day earlier, had shocked the world by announcing he would retire in three weeks because of fatigue and advanced age.
Sullivan gave part of his homily in Spanish, eliciting nods and occasional laughter.
He ended by asking for an "alleluia to me, that I may faithfully teach and sanctify . . . this local community."
Hundreds of priests and area bishops and religious leaders from other faiths attended the 21/2-hour service. Concelebrating the Mass with Sullivan were Archbishops John Myers of Newark, N.J., and Charles J. Chaput of Philadelphia.
Cardinals Timothy Dolan and Edward Egan, the current and former archbishops of the giant New York Archdiocese, sat in front seats but did not come to the altar for the consecration.
A modern, octagonal structure with exposed wooden beams, St. Agnes has the largest seating capacity in the diocese and serves as host for many of its major ceremonies. Galante was installed as bishop there in April 2004.
Although the church bears the name of St. Agnes, it is now the seat of Our Lady of Hope parish.
In 2008, Galante announced he was closing or merging nearly half of the diocese's 124 parishes - including St. Agnes - in what would become the most sweeping consolidation of any Catholic diocese in the history of the United States.
Although driven in part by the declining number of active priests in the diocese, Galante often said the consolidation was intended to create larger, more "vibrant" parishes like those he encountered during his 20 years as a bishop in Texas.
A native of Philadelphia, Galante will retire to Somers Point, Atlantic County, where he has a home. He has offered to help with confirmations and to advise Sullivan when asked. At last month's news conference announcing his appointment, Sullivan said he was coming to Camden with "no agenda" other than to "listen and learn."
In closing remarks at the end of the Mass, Egan praised Sullivan as "a priest first and foremost" who "loves the poor" and was "a hero to the Hispanic communities" he served.
Egan ended on a cautionary note, however. "Wait till you hear him sing," he said. "The Irish songs are endless. Be sure you have an escape."
He was followed by Dolan, who jokingly credited Sullivan's appointment with Benedict's historic decision to retire.
Benedict "asked his aides, 'Is Camden taken care of?' " Dolan said. " 'Then, I can rest.' "
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