It was believed that Bishop, of Thornton Heath, had been planning to attack Baitul Futuh Mosque, in Morden.
He was jailed for four years for possessing an explosive substance with intent to endanger life at Kingston Crown Court on Wednesday.
He had been charged with preparing an act of terrorism, but prosecutors accepted a guilty plea on Monday.
Judge Peter Lodder said: "The detonation of one or more of these fireworks at Morden mosque may have risked the lives of those nearby."
Bishop, who has a history of mental health issues and drug abuse, said he heard voices in his head.
He said the attack would have been revenge for the Manchester Arena bombing in 2017 and that a victim of the attack had told him to do it.
The court had heard how the 41-year-old had repeatedly searched for memorials to the youngest victim of the attack - eight-year-old Saffie-Rose Roussos.