"I will engage myself in lifting all the non-nuclear sanctions during the coming four years and bring back the grandeur of Iran and the Iranian people", President Rouhani had said during a televised debate on Friday focused on economy.
The coalition between the two conservative nominees will benefit the country's economy in a post-election era, if Raeisi manages to assume power through the election.
A conservative candidate has dropped out of Iran's presidential election to back a hard-liner challenging moderate President Hassan Rouhani.
Raisi has been touted as a frontrunner to succeed the country's supreme leader, Ayatollah Ali Khamenei.
Rouhani alluded to this controversy during a campaign rally recently, saying: "The people of Iran will announce in this election that they don't accept those who only knew executions and prison for 38 years".
Rouhani is standing against five other candidates, mostly hardliners, on May 19, with a run-off a week later if no candidate wins more than 50 per cent of votes in the first round.
Mr Raisi, is now the head of the powerful Imam Reza shrine and charitable foundation in the holy city of Mashhad and, in addition to attracting support from traditional conservatives, is seen as the favoured candidate of the security establishment.More news: Dangerous Severe Weather Possible Tuesday
That's exactly the kind of voter Rouhani needs to inspire.
The landmark nuclear deal struck in Vienna between Iran and a coalition of Western powers in 2015 aimed to reduce the global nuclear threat posed by Iran.
Raisi thanked Qalibaf for his support, calling it a "revolutionary act", according to the semi-official Tasnim news agency.
Supporters of the PMOI have also taken their movement to the streets, hanging banners reading "No to sham elections" or pictures of the President of the Iranian Resistance, Maryam Rajavi, in major cities across the country. So no matter who becomes Iran's next president, they will try and keep this nuclear agreement.
He has saved much of his most stinging criticism for Qalibaf, whose withdrawal now means Rouhani's campaign has to adapt for the final few days, said Foad Izadi, a member of the Faculty of World Studies at the University of Tehran who is a critic of the nuclear and Rouhani's foreign policy.
Raisi has pledged to support the poor with a monthly cash payment equivalent to $65 - about a sixth of what a menial laborer makes in a month. "In Tehran, his votes will go mainly to Rouhani but outside Tehran his supporters will vote for Raisi", said political analyst Hamid Farahvashian.
It was the culmination of a series of increasingly aggressive campaign attacks by Rouhani, a 68-year-old moderate cleric, who in recent weeks has lashed out at conservatives over issues from freedom of speech to corruption and wealthy institutions that don't pay tax.