As we all Believe that prophet Muhammad (peace be upon him) was a human Being.

He was also given messengership by Allaah Almighty.He was sent to deliver His message into all mankind

One of the Beauty of this religion was God's protection for the message and the messenger of God

As Allah Says,
يَا أَيُّهَا الرَّسُولُ بَلِّغْ مَا أُنْزِلَ إِلَيْكَ مِنْ رَبِّكَ ? وَإِنْ لَمْ تَفْعَلْ فَمَا بَلَّغْتَ رِسَالَتَهُ ? وَاللَّهُ يَعْصِمُكَ مِنَ النَّاسِ ? إِنَّ اللَّهَ لَا يَهْدِي الْقَوْمَ الْكَافِرِينَ ?67?
(interpretation. of the meaning ??)
O Messenger, announce that which has been revealed to you from your Lord, and if you do not, then you have not conveyed His message.And Allah will protect you from the people.Indeed, Allah does not guide the disbelieving people.
(Chapter 5 Verse 67)

Allaah clearly mentioned in this verse that He will protect Messenger of Allaah.

Allah protected him from every harms done by his enemies

even When the jewish woman placed poison in his food the food spoke out and protected him when he was about to eat.

A Jewish woman came to the Messenger of Allah, peace and blessings be upon him, with a poisoned sheep and he ate from it.She was brought to him and he asked her about it.She said, “I wanted to kill you.”

 The Prophet said, “Allah has given you no authority over me.” It was said, “Should we kill her?” The Prophet said, “No.”
Sahih Bukhari 2474, Sahih Muslim 2190

So this incident had nothing to do with The message of Islam

Prophet survived due to Allah's help

As Allah says:
يُرِيدُونَ لِيُطْفِؤُوا نُورَ اللَّهِ بِأَفْوَاهِهِمْ وَاللَّهُ مُتِمُّ نُورِهِ وَلَوْ كَرِهَ الْكَافِرُونَ(8)
(interpretation. of the meaning ??)
They want to extinguish the light of Allah with their mouths, but Allah will perfect His light, although the disbelievers dislike it.
(Chapter 61 verse 8)

The story of poison was happned after returning khaybar.
And he died three years after the incident .