The Gospel of Jesus: Guidance and Light
[5:46] Subsequent to them, we sent Jesus, the son of Mary, confirming the previous scripture, the Torah. We gave him the Gospel, containing guidance and light, and confirming the previous scriptures, the Torah, and augmenting its guidance and light, and to enlighten the righteous.
[5:47] The people of the Gospel shall rule in accordance with GOD’s revelations therein. Those who do not rule in accordance with GOD’s revelations are the wicked.
For each people God has given guidance for them to follow. Ultimately they can follow the Quran as it is the ultimate reference, but if they don’t have the Quran then they should follow their own scripture. A Christian or a Jew that has not received the Quran, should follow their own scripture.
Message of Jesus
https://www.youtube.com/watch?v=dT8_faUmR1w
[22:52] We did not send before you any messenger, nor a prophet, without having the devil interfere in his wishes. GOD then nullifies what the devil has done. GOD perfects His revelations. GOD is Omniscient, Most Wise.
[6:112] We have permitted the enemies of every prophet – human and jinn devils – to inspire in each other fancy words, in order to deceive. Had your Lord willed, they would not have done it. You shall disregard them and their fabrications.
https://en.wikipedia.org/wiki/Brothers_of_Jesus
“The New Testament describes James, Joseph (Joses), Judas (Jude) and Simon as brothers of Jesus. Also mentioned, but not named, are sisters of Jesus. Some scholars argue that these brothers, especially James, held positions of special honor in the early Christian church.”
Quran Talk Blog 