What is the method of repentance for a young man and woman who committed adultery, leading to the girl's pregnancy, knowing that the girl was born to a Muslim father and a Christian mother without marriage?

Adultery is one of the gravest major sins, and Allah has coupled it with polytheism and unlawful killing in the Quran. Therefore, those who commit adultery must repent, seek forgiveness, and increase their righteous deeds, for Allah accepts the repentance of those who repent. Abortion of a pregnancy resulting from adultery is not permissible, as it is an assault on a soul. If the fetus is born alive, it is attributed to its mother.