Matthew 11:27 NIV
All things have been entrusted to Me by My Father. No one knows the Son except the Father, and no one knows the Father except the Son and those to whom the Son chooses to reveal Him.
John 14:9-11 NIV
Jesus answered: “Don’t you know me, Philip, even after I have been among you such a long time? Anyone who has seen me has seen the Father. How can you say, ‘Show us the Father’? Don’t you believe that I am in the Father, and that the Father is in me? The words I say to you I do not speak on my own authority. Rather, it is the Father, living in me, who is doing his work. Believe me when I say that I am in the Father and the Father is in me; or at least believe on the evidence of the works themselves.
John 5:18 NIV
Jesus answered: “Don’t you know me, Philip, even after I have been among you such a long time? Anyone who has seen me has seen the Father. How can you say, ‘Show us the Father’? Don’t you believe that I am in the Father, and that the Father is in me? The words I say to you I do not speak on my own authority. Rather, it is the Father, living in me, who is doing his work. Believe me when I say that I am in the Father and the Father is in me; or at least believe on the evidence of the works themselves.
If the Messenger "made up something", how would he be punished?
Sahih al-Bukhari 4428
The Prophet (ﷺ) in his ailment in which he died, used to say, “O `Aisha! I still feel the pain caused by the food I ate at Khaibar, and at this time, I feel as if my aorta is being cut from that poison.“