Is sheltering a girl who is pregnant out of wedlock in one's home until she gives birth considered a sin, and what steps should be taken toward her; should she be expelled or left for the sake of Allah?

Hosting a disobedient girl is an act of kindness towards her and a preservation of her faith. She must be warned of Allah and encouraged towards sincere repentance, without despairing of Allah's mercy, for Allah Almighty says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" [Quran 39:53]. One must avoid gloating over her or shaming her for her sin. Measures must be taken to preserve religious integrity, such as lowering the gaze, ensuring that men do not seclude themselves with her, and providing a private room for her.