First, religions(islam,christianity,judisim) arent man made but prophets introduced them and they are humans, this person is the same as these mentioned in the quran: وَقَالُوا أَسَاطِيرُ الْأَوَّلِينَ اكْتَتَبَهَا فَهِيَ تُمْلَىٰ عَلَيْهِ بُكْرَةً وَأَصِيلًا surat furqan 5-8
5. And they say: "Tales of the ancients, which he has written down, and they are dictated to him morning and afternoon."
6. Say: "It (this Qur'an) has been sent down by Him (Allah) (the Real Lord of the heavens and earth) Who knows the secret of the heavens and the earth. Truly, He is Oft-Forgiving, Most Merciful."
7. And they say: "Why does this Messenger (Muhammad ) eat food, and walk about in the markets (like ourselves). Why is not an angel sent down to him to be a warner with him?
8. "Or (why) has not a treasure been granted to him, or why has he not a garden whereof he may eat?" And the Zalimun (polytheists and wrong-doers, etc.) say: "You follow none but a man bewitched."
Also, for the quran, if you understand arabic you will be sure that it is impossible for a human to make a quran, so our book alone is evidence of the existence of good, the quran holds many secrets and you can type in google: miracles of the quran, and read