The pontiff, in an impassioned speech in St Peter's Square in Rome, urged Christians to 'drive out evil' and emphasised the importance of baptism in order to exorcise demons.
According to the pope, those who are baptised are given the power to fight against the devil - with exorcism, or self-cleansing through prayer, becoming an essential part of Christian life.
He said the sacrament of baptism 'enables those who receive it to fight against the spirit of evil' - adding that 'all Christian life is a battle' and that believers should take precautions against the deceit of the devil.
'We know from experience that the Christian life is always prone to temptation, especially to the temptation to separate from God, from his will, from communion with him, to fall back into the webs of worldly seductions,' he said.
'And baptism prepares and strengthens us for this daily struggle, including the fight against the devil who, as St. Peter says, like a lion, tries to devour and destroy us.'
'It is hard to fight against evil, to escape from its deceits, to take strength again after an exhausting struggle,' Francis said, 'but we must know that all Christian life is a combat.'
The pontiff advocated prayer and the sacraments as the best way to exorcise evil spirit during Wednesday's weekly address.
Comment: Forms of self discipline are probably the best ways to deliver oneself from evil.
He did, however, warn that there was no quick fix to eradicating the devil - and that baptism was just a tool which enables Christians to fight against evil.
He explained that adults preparing for baptism are subject to 'repeated exorcisms pronounced by the priest,' Francis said.
'That is, prayers that call for liberation from all that separates from Christ and prevents intimate union with him.'
Baptism 'is not a magic formula,' the pope said, 'but a gift from the Holy Spirit that empowers those who receive it 'to fight against the spirit of evil.'
The statements are not the only controversial decree the pope has issued this week.
On Tuesday he renewed his pledge that sick toddler Alfie Evans should be flown to Rome to receive treatment - despite the ruling of the UK courts that he should remain in the UK.
He also met with the sick boy's father Tom Evans in Rome who said pope Francis 'looked him in the eye and told him he was doing the right thing'.
Pope Francis has met with Alfie Evans' father (pictured) as he renewed his pledge to bring the sick child for treatment in Rome
Comment: All around us there are serious signs of change, and one wonders whether comments from religious leaders of increasing spirit possession, 'end times', and the evil we see manifesting on our planet, are part of these changes: