The president urged for unity after meeting with leaders of the APC and PDP on Friday.
The meeting took place at the Banquet Hall of the Presidential Villa, Abuja, on Friday, August 25, 2017.
Speaking at the meeting that was also attended by Vice President Yemi Osinbajo, President Buhari said, "Multi-party democracy is a very tried and tested form of government. Opposition does not mean hostility, enmity or antagonism. Democracy needs opposition, one which is vibrant but responsible.
"I am imploring all Nigerians to continue praying for peace and prosperity in Nigeria."
ALSO READ: President Buhari meets APC, PDP leaders
The APC delegation at the meeting was led by national party chairman, John Odigie-Oyegun, while the PDP's delegation was led by caretaker chairman, Senator Ahmed Makarfi.
Also speaking after the meeting, Makarfi welcomed the president back to his official duties and pledged to him the full backing of the opposition PDP.
He said, "We believe the President of our country - regardless of what party flag he or she flies - is our President.
"We will never wish ill of anyone, not to talk of the person saddled with the responsibility of leading Nigeria.
"PDP ready to offer legitimate, decent opposition. We will do this to keep govt in check, but ultimately for the benefit of Nigeria.
"We assure you of as much cooperation as an opposition party can give - after all the role of the opposition is to take over power."
Odigie-Oyegun also praised the president's efforts to unify the country, saying that he has "sent out a message that he's President of all Nigerians, regardless of party/religion/ethnicity."
Members of the APC delegation at the meeting include the party's National Legal Adviser, Muiz Banire, former Senate President, Ken Nnamani, Senator Olorunnimbe Mamora, Prince Tony Momoh, among others while Senator Ben Obi was part of the delegation of the PDP along with other members of the party's National Working Committee.