The Jews could just not believe that God would become a man. Even though Isaiah prophesied “Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.” which translated means “God with us.” The religious leaders thought it blasphemy to say He was equal with God and would not believe the scriptures that foresaw the works He would do. For us belief in the Word is just as important. Modern doubters will agree the Word is inspired by the Holy Spirit but then claim it’s been altered or mistranslated over time. How could God supernaturally inspire the writing of 66 books over thousands of years and then not supernaturally preserve His Word?
“…every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.” (1John 4:3)