Ibn Kathir reports from Musnad Ahmed (ra) that the Prophet (saw), during his time in Medinah went to visit a young ailing Jewish boy. Muhammad (saw) at the time, as a ruler, along with his companions Abu Bakr and 'Umar (ra) entered the house and found the Jewish boy's father reading the Torah alongside the bed to comfort his son's soul. Due to the presence of Muhammad (saw), the man closed the Torah. Muhammad (saw) asked the man "By the One who revealed the Torah, do you read in it about me and about the news of my baath (coming) or not?" The father of the Jewish boy shook his head and said "no?"
Upon hearing this, his dying son spoke up and said, "I swear by the One who revealed the Torah that we find in our book the news of your characteristics and your baath (coming), and bear witness that you are the Messenger of Allah."
The boy died soon afterwards and the Prophet (saw) said, "He is a Muslim, remove the Jews from here." Then, he (saw) prepared for the boy's burial and funeral prayer. Understanding the way in which Muhammad (saw) delivered the Da'wah of Islam at all times and to all people, even when they were on their deathbed should make us realise the seriousness of this duty and the priority that the Messenger of Allah (saw) gave it. Muhammad (saw) did not hesitate to challenge the belief of the Jew, even when he was facing a tragic time for his family. We should realise the seriousness of delivering the Da'wah (Message) because those who die without being delivered Islam will have a case against the Muslims on the Day of Judgement. As we see in the events mentioned above, Muhammad (saw) saved himself first by delivering Islam and furthermore saved that boy from the Hellfire.