The pope celebrated a private Mass for Angola's clergy and laypeople in the modernist Sao Paulo church, which along with much of the surrounding neighbourhood has been freshly painted and upgraded for his visit.
He praised the work of activists within the Church, and called on them to work to convert people to Catholicism, saying evangelising remains as important today as it was when Catholics first arrived in this region of Africa 500 years ago.
"Today it is up to you, brothers and sisters, following in the footsteps of those heroic and holy heralds of God, to offer the risen Christ to your fellow citizens," he said to the invitation-only crowd.
"So many of them are living in fear of spirits, of malign and threatening powers. In their bewilderment they end up even condemning street children and the elderly as alleged sorcerers," he said.
The issue has particular resonance in Angola, where traditional and home-grown faiths are flourishing, even though some sects have been linked to child abuse and human sacrifice.
Benedict criticised the idea that seeking to convert people was an affront to believers of other faiths.
"We do no injustice to anyone if we present Christ to them and thus grant them the opportunity of finding their truest and most authentic selves, the joy of finding life," he added.
Sao Paulo claims the largest congregation in Luanda, with seating for 1,500 people. Next door is the headquarters of Radio Ecclesia, a Catholic radio station that is one of the few independent voices in Angolan media.
Local Church leaders hope the pope's visit will push Angola's government -- run by the formerly Marxist Movement for the Popular Liberation of Angola -- to allow the station to broadcast nationwide, rather than only in the capital.
In a speech at President Jose Eduardo dos Santos's residence late Friday, Benedict urged African leaders to allow greater press freedom, as he made a stern call for the continent to do more to fight poverty and corruption.
Dos Santos has ruled Angola for 30 years, and the country is ranked among the most corrupt in the world by Transparency International.
But in a country still recovering from decades of war, two thirds of the population lives on less than two dollars a day, despite Angola's oil riches.
"The multitude of Angolans who live below the threshold of absolute poverty must not be forgotten. Do not disappoint their expectations," Benedict said Friday.
He called on Africa to show "a determination born from the conversion of hearts to excise corruption once and for all".
"Armed with integrity, magnanimity and compassion, you can transform this continent, freeing your people from the scourges of greed, violence and unrest," he said.
Benedict has also sought to reinforce Catholic teachings on social issues, taking aim at a part of the African Union's charter that guarantees women a right to an abortion in cases of rape, incest, or major health risks to the mother, saying abortion was not a health issue.
Those remarks followed his controversial denunciation of condoms as a tool to prevent AIDS, which has sparked an international uproar among activists and some governments.