Bishop Onaga said this in his sermon at the ordination of 26 priests and the 50th Anniversary of the Sacred Heart Seminary, Nsude (Junior Seminary) in Enugu.
He told the priests to plan retreats for their parishioners, pay more attention to prayers, and not go on crusades.
Onaga was at the 55th anniversary of his alma mater when he told priests not to start prayer groups but instead to take their members to approved places to pray, like Ugwu D Nso, a monastery, and other places.
"Don't serve in a Pentecostal way, and be careful about starting prayer groups," he told them.
He told the newly ordained priests that they should try to be holy and not get involved in worldly things.
Earlier, the rector of the seminary, Rev. Fr. Stanislaus Onodugo, said that the Bishop of Enugu, His Lordship Godfrey Okoye of blessed memory, came up with the idea for the seminary in 1972.
He said that priests and other people who had gone through the seminary since 1972 had become respected people.
"Today, the seminary can say that at least one bishop, Bishop Onaga, was in the second group of students to study here.
"We're also having a big party for the end of our 50th anniversary, which started on June 27."
Onodugo said, "Today, our dear bishop raised 26 deacons to the Order of the Priesthood, and we're glad that this is happening in our time."
The News Agency of Nigeria (NAN) says that Bishop Onaga entered the seminary in 1973 with the second group of students.