Why would god allow his messenger to be poisoned and die?
simple he was an IMPOSTOR!!
From Ibn Sa’d page 249:
Verily a Jewish woman presented poisoned (meat of) a she goat to the apostle of Allah. He took a piece form it, put it into his mouth, chewed it and threw it away. Then he said to the Companions: “Halt! Verily, its leg tells me that it is poisoned.” Then he sent for the Jewish woman and asked her; “What induced you to do what you have done?” She replied, “I wanted to know if you are true; in that case Allah will surely inform you, and if you are a liar I shall relieve the people of you.”
From Ibn Sa’d page 249: [different narrator]
The apostle of Allah and his companions ate from it. It (goat) said: “I am poisoned.” He [Muhammad] said to his Companions, “Hold you hands! because it has informed me that it is poisoned!” They withdrew their hands, but Bishr Ibn al-Bara expired. The apostle of Allah sent for her (Jewess) and asked her, “What induced you to do what you have done?” She replied, “I wanted to know if you are a prophet, in that case it will not harm you and if you are a king, I shall relieve the people of you. He gave orders and she was put to death.
I admire this jewish women, she brought an end to the murderous tyrant