Answer
Wa Alaykum Assalam Dear Mohammad,
Thank you for your question, and for contacting Ask About Islam.
Initially, we must be very careful in properly understanding the context of Quranic verses without assuming or adding words that are not part of the original text, even in a translation. So if a non-Muslim quotes a translation, we need to ask “which one?”.
If it is his own translation then he has obviously chosen to conveniently mistranslate to achieve his goal, which is distorting the message of Islam.
1. There is no where in verse 3:144 that mentions “All”. Most translations mention “Many”, which gives a completely different meaning than “All”.
{Muhammad (peace be upon him) is no more than a Messenger, and indeed (many) Messengers have passed away before him. If he dies or is killed, will you then turn back on your heels (as disbelievers)? And he who turns back on his heels, not the least harm will he do to Allah; and Allah will give reward to those who are grateful.} [Mohsin Khan]
{Muhammad is no more than a messenger: many Were the messengers that passed away before him. If he died or were slain, will ye then Turn back on your heels? If any did turn back on his heels, not the least harm will he do to Allah; but Allah (on the other hand) will swiftly reward those who (serve Him) with gratitude.} [Yusuf Ali]
{Muhammad is but a messenger, messengers (the like of whom) have passed away before him. Will it be that, when he dieth or is slain, ye will turn back on your heels? He who turneth back on his heels doth no hurt to Allah, and Allah will reward the thankful.} [Muhammad Pickthal]
Therefore, there is no contradiction because Jesus (peace be upon him) is still alive.
2. Again, there is no mention of who is the first Muslim in the entire Quran because it is obvious that Adam (peace be upon him) is the first Muslim, being the first human being and religion before Allah is Islam.
{Surely the (true) religion with Allah is Islam…} (Al-Imraan, 3:19)
Anti-Muslims have conveniently chose not to understand the context. For example:
{Say: Shall I choose for a protecting friend other than Allah, the Originator of the heavens and the earth, Who feedeth and is never fed? Say: I am ordered to be the first to surrender (unto Him). And be not thou (O Muhammad) of the idolaters.} (6:14)
It is obvious for any sensible reader that it clearly does not say that Muhammad (peace be upon him) is the first Muslim ever. The context here is that he was ordered during his lifetime to be the first Muslim or the first believer.
3. You are referring to the following claim that the Quran contains three contradictions:
a. “Eating of the tree of Zaqqum” (37:66) contradicts “eating only Dhari” (88:6).
b. “Eating of the tree of Zaqqum” (37:66) contradicts “eating only foul pus” (69:36).
c. “Eating only Dhari” (88:6) contradicts “eating only foul pus” (69:36).
The answer to this is as follows:
In the Quran interpretation (Tafsir) of Ibn Katheer, the explanation of verse 88:6 is: Ali bin Abi Talhah reported from Ibn Abbas that he said about “Dhari” that it is “A tree from the Hellfire”. Verse (69:36) is explained: Ar-Rabi and Ad-Dahhak both said: “It (Ghislin) is a tree in Hell.”
Verse 37:66 is obvious since it mentions the tree, Zaqqum.
So Allah gave three different names to the tree that the people of the hell will eat from. May Allah protect us from the hellfire! These are not just names. In Arabic names are descriptive so this is telling us that this tree produces food, a fruit if we may say, which is dry (Dhari), thorny (Zaqqum), and contains pus (Ghislin):
A tree in our world feeds from the earth to grow and produce fruits. This particular tree is in the hellfire feeds from the remains that fall in the hellfire; the pus that flows from the people of the hell. In addition to its own thorny and dry fruit; so all the people of the hellfire feed from that same tree and that is their only food.
Since it is very dry it makes them thirsty so they drink boiling water to attempt to quench their thirst. Since it is thorny it cuts their intestines along the boiling water but Allah regenerates their intestines and the punishment is repeated over and over. The pus is just to make it disgusting with an awful taste. Again may Allah protect us from the torment of the hellfire.
May Allah guide the entire humanity so they may enter the Paradise.
I hope this helps answer your question.