Mohammad foretold in the Bible?

Muslims believe that their prophet is mentioned in the Bible. They must believe this because of a particular verse in the Qur'an:
Those who follow the Apostle, the unlettered Prophet, whom they find mentioned in their own (Scriptures) - in the Law and the Gospel. Surah 7.157
Unfortunately (for Muslims) when one looks for these references to Mohammad in the Old Testament (the Law) and the New Testament (the Gospel) there appears to be no such mention. This has led to three distinct (but by no means mutually exclusive) approaches by Muslim "scholars".
i.  claim the scriptures have been tampered with
ii.  put unusual interpretations on esoteric verses so they fit with their ideas

i. claim the scriptures have been tampered with. Muslims base this belief upon two verses in the Qur'an which appear to suggest that the Christians and Jews have indeed changed their scriptures:
 "They (i.e. Jews and Christians) changed words from their contexts and forgot a good part of the message given to them, and you will continue to find them -except a few among them- bent on new deceits…" (al-Ma'idah: 13)  
"O People of the Book, now has come to you Our Messenger, clarifying to you much of that you used to conceal of the Book and passing over much (that is now unnecessary)." (al-Ma'idah 5:15)
This is a great get-out clause for Muslim miracle seekers since anything in the Bible that seems to contradict the Qur'an (such as the story of Jesus being crucified or the belief in the Trinity) can simply be explained away as having been "tampered with". So when doubters say there appear to be no obvious references to a "Mohammed"  in the Bible, this is often a first line of defence.

A good example of this can be seen in a recent mail from my Muslim friend in which he said that "we cannot know for sure what has been edited out or in over the centuries." He went on to state:
"That such editing happens is certain, as comparison with different versions of the Bible shows.
He then went straight onto  ii.  put unusual interpretations on esoteric verses so they fit with their ideas
For example  in the King James Bible Psalm 84 states that the Jews make pilgrimage to “Bacca” (a name for Mecca) whereas in the later Revised English Bible Psalm 84 changes “Bacca” to “the waterless valley” (which could be anywhere). The Jews were expecting another prophet to come after Jesus and they expected him to come from an area in modern day Arabia. 
There was much more in his interesting mail which I intend to examine in future posts. For now, however, I'd like to deal with the common belief (among Muslims) that Mecca is mentioned in Psalm 84 and that thus the Bible relates how Jews used to make a pilgrimage there and this fact has been wickedly expunged from the record in an attempt to mislead the common people and hide the truth...

The following paper by Toby Jepsom does an excellent job of disproving the hypothesis. Since I can't improve upon it I shall simply reproduce it:
The whole psalm focuses on God's sanctuary and how the writer loves to spend time there. The author is one of ‘the Sons of Korah’ and internal evidence points to it being written after the building of the temple in Jerusalem by Solomon. Because of the psalm's focus on the sanctuary, there are several phrases which describe features of it, enabling us to evaluate the claim that it is Mecca:
  • v.1 - ‘How lovely is your dwelling place, O Lord Almighty!’
  • v.3 - ‘... a place near your altar, O Lord Almighty ...’
  • v.4 - ‘Blessed are they who dwell in your house
  • v.7 - ‘They go from strength to strength, till each appears before God in Zion.’
  • v.10 - ‘I would rather be a doorkeeper in the house of my God ...’
These five points count heavily against the claim outlined above. Firstly (I am open to correction on these points), I do not suppose that Muslims would accept the idea of Allah dwelling in the Ka'aba. I certainly am not aware of this way of thinking in Islam. On the other hand, the Bible repeatedly mentions the temple in Jerusalem as God's dwelling place, even though he is not limited to a building. In 1 Kings 8:27, Solomon, on the completion of his great temple, said this:
This makes it clear that the idea of God dwelling in the temple is figurative and not that he is limited to one building. However, it shows clearly that this way of thinking is found in the Bible.
Secondly, I am unaware of any altar which is given prominence at the Ka'aba, whereas the altar was an integral part of the tabernacle and then the Jerusalem temple, necessary for the sacrificial system instituted by God. (Exodus 27:1-8, 1 Kings 8:64).
Thirdly, the Ka'aba is empty and certainly no humans dwell in it. Yet Psalm 84 mentions those who dwell in God's house. This makes no sense unless it is the Jerusalem temple, which had rooms within its courts (1 Chronicles 28:11,12) for those who were responsible for its upkeep and ceremony.
Fourthly, the pilgrims in Psalm 84 are certainly not on their way to Mecca, as their destination is given as Zion. Mount Zion is one of the hills on which Jerusalem is founded. In the Bible Zion is often used synonymously with Jerusalem (Isaiah 2:2).
This point is made even stronger by examining the word used for ‘pilgrimage’ in Psalm 84:5. I don't claim to know much Hebrew or Arabic, so someone who does is welcome to correct me on this. However, I do know that both languages are Semitic and close in many ways, having the same or similar words for lots of things. That being the case, we might expect the Hebrew word translated here as ‘pilgrimage’ to be similar to the Arabic hajj. In fact, it is not. The only similar Hebrew word that I could find in my exhaustive concordance was hag, which is often translated as ‘festival’ and therefore seems to me to be in some way related to the Arabic hajj.
The Hebrew word used in Psalm 84:5 is from a completely different root to this and is usually translated as ‘road’ or ‘highway’. Thus it seems from a brief consideration that the phrase is literally like saying in English ‘those ... who have set their hearts on the highway’, meaning the way they must take to get to Jerusalem. So even the ideas of pilgrimage in the Bible and the Qur'an have a different emphasis. Just because the English translation of Psalm 84:5 says ‘pilgrimage’ we can't simply equate it with the Hajj.
Fifthly, there is no recognised function of doorkeeper for the Ka'aba, as far as I am aware. However, this was an official job at the Jerusalem Temple (2 Kings 25:18).
What Then is the Valley of Baca?
Baca has been translated either as ‘weeping’ or ‘balsam trees’ (which grow in dry places). It could be a real place, in which case it was a valley through which the pilgrims passed during their journey. Alternatively, it could be figurative. In this interpretation, even the dry, arid places through which the pilgrims pass are brought alive by their expectant joy as they near their destination. In either case, their pilgrimage is clearly to Jerusalem, as evidenced by the rest of the psalm. Why on earth would Jews, living in Israel and on their way to Jerusalem, take a huge detour through Mecca?
Whatever our conclusion as to the true identity of the valley of Baca, I think that I have made it fairly clear that the only link between it and the Bakkah of the Quran is a superficial similarity in name. The further details about the location point away from the two being identical. Since that is the case, why should we not link the Bakkah of surah 3:96 with any other place having a similar sounding name? Here is a quote from the article mentioned above:
This shows that there are other places with similar names. Why then, do we not hear people claiming that the Quran is referring to these? It seems to me that it is because there is a prior commitment on the part of some to finding evidence for the Quran in the Bible. This, if found, would strengthen the claim that Islam is completely in line with all God's earlier revelations. However, in this case, it cannot be sustained.
I hope that this short paper has made it clear that the Baca of the Bible cannot be the Bakkah of the Qur'an. Rather than being a justifiable theory, it seems that some people, in their zeal to verify the Qur'an by using the Bible, have jumped all too quickly to a mistaken conclusion. A few superficial similarities are offset by several clear contradictions. It is often easy to bend the facts to fit our own theories, rather than forming our theories around the facts. This is never easier than in religion. Both Christians and Muslims are open to this temptation: I hope that fair-minded people will see this as a case in point.