How can one refute the misconception of non-Muslims that the Gospel has not been distorted, based on verses 47 and 68 from Surat Al-Ma'idah?

The Torah and the Gospel are from the revelation of God, sent down as light and guidance. The Qur’an came to confirm them and to be dominant over them.

The Qur’an mentioned that the available versions of the Torah and the Gospel have been subjected to alteration, concealment, and addition. A group of them distorted the word of God after understanding it, concealed much of what was revealed, and added to it what was not from it, writing with their own hands and falsely attributing it to God.

Nevertheless, the Qur’an affirmed the existence of some truth in these books and called their followers to uphold this truth, making it a proof against them. Some verses mentioned the continued validity of God's حكم (judgment/ruling) in the Torah, commanded the people of the Gospel to judge by what was revealed therein, and stated that Prophet Muhammad (peace be upon him) is mentioned among them.

The preservation of the Torah and the Gospel was entrusted to their scholars. God did not undertake their preservation as He did with the Qur’an.

In conclusion, the versions of the Torah and the Gospel contain truth and "God's حكم," but they include words from humans falsely attributed to God. They suffered from deficiencies due to concealment, and from verbal and semantic distortion. Therefore, one must believe in everything God has revealed and adhere to it, and not use some verses as an argument while abandoning others.