What is the refutation to a Christian who cites the verse "And We ransomed him with a great sacrifice" (Qur'an 37:107) to prove the doctrine of atonement in the Qur'an, and claims that the great sacrifice is "the Son of God," and that the intention behind it is to instill the doctrine of atonement by blood, as in the Book of Hebrews?

Firstly: From the Quran and Sunnah, forgiveness is attained for wrongdoers and sinners without the shedding of blood, and human blood is sacrosanct unless proven otherwise. Among the causes of forgiveness are: 1. Repentance (Tawbah): Allah accepts the repentance of His servants and forgives all sins. 2. Seeking Forgiveness (Istighfar): Allah forgives those who seek His forgiveness. 3. Good Deeds and Righteous Actions: They erase evil deeds, such as the five daily prayers, Ramadan, Hajj, and following a bad deed with a good one. 4. The Supplication of Believers: Their prayer over the deceased (funeral prayer) intercedes for the dead. 5. Acts of Piety for the Deceased: Such as charity, freeing a slave, Hajj, and fasting on their behalf if they had an obligatory fast. 6. The Intercession of the Prophet (peace be upon him) and others on the Day of Judgment. 7. Calamities: They expiate sins in this world. 8. What happens in the grave, such as the trial (fitnah), the compression (daghtah), and the terror (raw'ah): These expiate sins. 9. The horrors, distress, and hardships of the Day of Judgment: These expiate sins. 10. Allah’s Mercy, Pardon, and Forgiveness: Allah forgives what is less than polytheism for whomever He wills.

Secondly: The invalidity of the doctrine of atonement in Christianity: The current Christian religion is distorted and full of contradictions, among them the doctrine of the crucifixion of Christ as atonement for original sin. This claim is false for the following reasons: 1. Accusing Allah of injustice: How can Allah punish Jesus for a sin he did not commit, and kill him by crucifixion merely for eating a fruit? 2. Accusing Allah of incapability: The claim that Allah was unable to forgive Adam’s sin except by crucifying His son, which is inconsistent with Allah’s power. 3. The Torah curses anyone who is hanged on a tree: This makes Christ cursed according to their belief. 4. Belief in Christ alone being sufficient for forgiveness regardless of deeds, which leads to corruption.

Forgiveness in Islam has multiple causes and is not related to the shedding of human blood, whereas the doctrine of atonement in Christianity contradicts reason and divine justice.