In order for Christians to really understand why Muslims accept the Prophet Muhammad (pbuh) and his teachings, I would suggest that Christians should try praying in the manner that the Lord Himself wants His servants to worship Him i.e. the way how the Biblical Prophets (peace be upon them all) themselves prayed to their Lord.
Genesis 17:3 "And Abram fell on his face: and God talked with him, saying,"
Genesis 17:17 "Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?"
Exodus 34:8 "And Moses made haste, and bowed his head toward the earth, and worshipped."
Numbers 16:20-22 "And the LORD spake unto Moses and unto Aaron, saying, Separate yourselves from among this congregation, that I may consume them in a moment. And they fell upon their faces, and said, O God, the God of the spirits of all flesh, shall one man sin, and wilt thou be wroth with all the congregation?"
Joshua 5:14 "And he said, Nay; but as captain of the host of the LORD am I now come. And Joshua fell on his face to the earth, and did worship, and said unto him, What saith my Lord unto his servant?"
Ezekiel 9:8 "And it came to pass, while they were slaying them, and I was left, that I fell upon my face, and cried, and said, Ah Lord GOD! wilt thou destroy all the residue of Israel in thy pouring out of thy fury upon Jerusalem?"
2 Chronicles 20:18 "And Jehoshaphat bowed his head with his face to the ground: and all Judah and the inhabitants of Jerusalem fell before the LORD, worshipping the LORD."
Ezekiel 11:13 "And it came to pass, when I prophesied, that Pelatiah the son of Benaiah died. Then fell I down upon my face, and cried with a loud voice, and said, Ah Lord GOD! wilt thou make a full end of the remnant of Israel?"
Matthew 17:6 "And when the disciples heard it, they fell on their face, and were sore afraid."
Matthew 26:39 "And he (Jesus) went a little farther, and fell on his face, and prayed, saying, O my Father, if it be possible, let this cup pass from me: nevertheless not as I will, but as thou wilt."
I would suggest that they try praying to seek guidance from their Lord in this manner for a spell in the privacy of their homes, preferably in the direction of Jerusalem if they like and I would also suggest that they do this immediately after they have taken their bath.
I feel that the main reason why Christians find it so hard to understand Muslim beliefs is because they are reluctant to prostrate to the Lord and therefore I am confident that after praying in this manner, Christians would then be able to understand, God willing, why Muslims readilly accept the Prophet Muhammad (pbuh) as the Messenger of God and why we thank the Lord every single day of our lives that He has sent him to us as a mercy for all of humankind.
“We have sent you (O Muhammad) not, but as a mercy for the Alameen (mankind, jinn, and all that exists).” … [al-Qur’an, surat Al-Anbiya’, (Verse 107)]