The three tests for the Holy Prophet

Through successive chain of narrators reaching the Noble Shaikh Ja'far bin Mohammad bin Qawlawayh Qummi, who through his chain of transmitters relates from Hammad bin Usman, who in turn relates from Imam Ja'far as Sadiq (a.s) that when Prophet Mohammad (s.a.w.s) was taken to the heavens (on the night of Me'raj, Ascension), he was told by Allah Almighty that I will test you by three ways so as to know the extent of your patience. The Prophet re­plied, 

"I surrender to your command O Allah! But I lack the ability to forbear Your trial. Please tell me as to what the three ways are"?

It was said, the first is hunger and giving preference to the needy over yourself and your family.
The Prophet replied,
"I accept O Lord! And am satisfied and bow my head in front of your Command, while favour and patience are from You alone."

Second being the lies which people will attribute to you, the fear and severe danger, and donating your life in My way, and fighting the forces of disbelief with your life and wealth, and patience upon the sever­ity and difficulty which will befall you at their hands and the hands of the hypocrites, and the sorrows and troubles and the wounds of the battle­field.
The Prophet replied,
"I accept O Lord! And am satisfied and bow my head in front of Your Command, while favour and patience are from You alone."

While the third one being the sufferings and martyrdom which your family will have to bear after your death. Then your cousin (Imam Ali) will have to face vilification, reproach and suppression and will be frustrated besides falling prey to severity and oppression and will ultimately be martyred.
The Prophet replied,
"I accept O Lord! And am satisfied and bow my head in front of Your Command, while favour and patience are from You alone.”

As regards your daughter (sayyedah Fatemah), she too will have to bear the hardships (and all the affictions which would befall her were related to him). Then this daughter of yours will have two sons from your cousin, one of whom (Imam Hasan) will be killed by a coward and his belong­ings will be looted and he will be wounded with a lance, while these acts of tyranny will be performed by the people of your nation (ummah).

The Prophet replied,
"I accept O Lord! And am satisfied and bow my head in front of Your Command, while favour and patience are from You alone."

As regards her second son (Imam Husain), the people will call him for a battle and kill him to the extent that his sons and whoever (from his family or friends) accompanying him shall also be killed. Then they will loot his family, and he will request for help from Me, but verily Martyrdom has been decreed for him and for those accompanying him. And his Martyrdom is a proof over all the people from the east to the west. And the heavens and the earth shall weep over him, and the Angels, who would not be able to assist him, shall lament too. Then I shall emerge a man (Imam Mahdi) from his progeny, by whose means I will assist you, and his spirit is near Me under the Empyr­ean."

Source: Nafasul Mahmoom by Sh. Abbas Qummi (ra)