It is easy enough to disprove this claim using Scriptures that date back to long before Muhammad was even born. And we're not talking mere hundreds of years before he was born, but thousands of years.
We have support from archaeology as well. This is the Moabite Stone, also known as the Mesha Stele, dated to around 830 BC:
The Moabite Stone is the oldest existing record of the name of the God of Israel, which we find inscribed on it:
Line 17 For I had devoted them to destruction for (the god) Ashtar Chemosh. And from there I took the
Line 18 vessels of Yahweh, and I presented them before the face of Chemosh...This is the very same name which God gave to Moses when he asked how God wished to be known among His people. Here are a few verses from each of Moses' 5 books which demonstrate this (text in brackets mine):
Genesis 4:1, Names of God Bible
Adam made love to his wife Eve. She became pregnant and gave birth to Cain. She said, “I have gotten the man that Yahweh promised.”
"So [Isaac] built an altar there, called on the name of Yahweh, and pitched his tent there. Isaac’s slaves also dug a well there."
For I am Yahweh your God, so you must consecrate yourselves and be holy because I am holy. You must not defile yourselves by any swarming creature that crawls on the ground.
“Tell Aaron and his sons how you are to bless the Israelites. Say to them: May Yahweh bless you and protect you; may Yahweh make His face shine on you and be gracious to you; may Yahweh look with favor on you and give you peace."
"See, the Lord your God has set the land before you. Go up and take possession of it as Yahweh, the God of your fathers, has told you. Do not be afraid or discouraged."
In Deuteronomy 18, Moses tells of God's promise of One Who would come after him and Who would do mighty miracles as Moses did. One Who would come from among the Israelites. One Who would bring the Word of YHWH God. Moses said:
17 Then the Lord said to me, ‘They have spoken well.
18 I will raise up for them a prophet like you from among their brothers. I will put My words in his mouth, and he will tell them everything I command him.
19 I will hold accountable whoever does not listen to My words that he speaks in My name.
Some 1,400 years later, God sent that Prophet. His name was Yeshua, and He came in the name of Yahweh. Literally.
Jesus came in the name of YHWH, the Great I Am, and He brought the salvation promised for all men through His sacrifice on the cross, but God had also warned of punishment for those who claimed to be prophets but who had not been sent by Him.
20 But the prophet who dares to speak a message in My name that I have not commanded him to speak, or who speaks in the name of other gods—that prophet must die.’ Deuteronomy 18
Almost 600 years after Jesus, Muhammad came along claiming to be sent by the God of Israel, but not bearing His Name. Had he come to the Israelites during Moses' time, his punishment would have been an instant death sentence for attempting to lead Israel away from their one God, Yahweh, and to the foreign god of the Ka'aba.
This is why it is so vital that we reach Muslims with the Gospel of Jesus Christ. They need to read the Bible for themselves to see that the Name of God is not a compound word which simply means, "the god," but Yahweh, Whose Name bespeaks the immense power, glory and authority that rightfully belongs to God alone. To serve any other than Yahweh means eternal punishment, a fate we would never wish on anyone.
We have one more hint of the importance of serving the right God. In it we find the divine thread that weaves together God's many thousands of years old plan to save us from our sins. That divine thread is found in yet another name.
The name of Messiah, YHWH's Anointed One.
His name is not "Allahshua."
The name "Jesus" was not chosen at random, no.
It is "Yeshua" in the original Hebrew, a name chosen to confirm God's Message and His plan for you and me.
Where Does Jesus Say, "I Am YHWH (God)" in the Bible?
Who is the Prophet of Deuteronomy 18:18-19?
Where is Jesus Prophetically Named in the Old Testament?
For more on the Moabite Stone, see:
Whose Land Is It Anyway? Part 1