The Word of the Holy Prophet Muhammad was
the Revealed Word of God

The Holy Prophet Muhammad spoke nothing but the revelation
from the Lord. This unique character, or exclusive distinction, of
the Holy Prophet has been declared by the Holy Qur'an as well as
in the ancient Scriptures:

Nor does he speak of (his own) inclination; It (the
wording) is naught but a revelation revealed (unto him.)

The Holy Prophet has been identified as such even in ancient

For Moses truly said unto the fathers, a Prophet shall the
Lord your God raise unto you of your brethren like unto
me; him shall ye hear in all things whatsoever he shall
say unto you.
And it shall come to pass that every soul which will
not hear "that Prophet" shall be destroyed from among
the people.
I will raise them up a Prophet from among their
brethren like unto thee, and will put my words in his
mouth; and he shall speak unto them all that I shall
command him.
And it shall come to pass that whosoever will not
hearken unto my words which he shall speak in my name,
I will require it of him. (Deuteronomy 18:18, 19)

Howbeit, when the Spirit of Truth is come, he will guide
you unto all truth for he shall not speak of himself but
whatsoever he shall hear, that shall he speak; he will
show you things to come. (St John's Gospel, 16:13)