Housing a criminal
The Prophet (sal Allahu alaihi wa sallam) said, “Allah has cursed the one who houses a criminal (innovator in religion).”
From the ones that Allah has cursed is the one who gives refuge to a criminal. This is a person who is a sinner, a disobedient slave who has torn down the limits of Allah and has earned himself or herself a dark reputation. This may include a prolific thief who transgresses against others or a drug trafficker who causes the corruption to spread in the society. Whoever offers accommodation to such a person, houses them, shelters them in their hospitality, defends them and hides them from the authorities is cursed. He/she is as guilty as they are assisting this person in continuing their actions and providing them with a refuge in the process.
As an alternative explanation the scholars have described him as the innovator in religion. The person who accepts to keep an innovator who spreads his poison in the community, leading people into the misguidance and away from the pure Sunnah is also cursed.
And Allah knows best!