Narrated Anas (radiallah anhu) :
The Prophet (saw) said, "The real patience is at the first stroke of a calamity."
[Sahih Al-Bukhari -Hadith 389]

al-Tirmidhi (2399) narrated that Abu Hurayrah (may Allāh be pleased with him) said: The Prophet (peace and blessings of Allāh be upon him) said: "Trials will continue to befall the believing man or woman in himself, his child and his wealth until he meets Allāh with no sin on him." Narrated by al-Tirmidhi (2399), classed as saheeh by al-Albaani in al-Silsilah al-Saheehah, 2280.

Muslim (2572) narrated that 'Aa'ishah (may Allāh be pleased with her) said: The Messenger of Allāh (peace and blessings of Allāh be upon him) said: "The believer is not harmed by a thorn or anything greater, but Allāh will raise him in status thereby, or erase a sin thereby."

al-Fudayl ibn 'Iyaad said: As long as people are doing fine, their true nature is concealed, but when calamity strikes, their true natures are revealed, so the believer resorts to his faith and the hypocrite resorts to his hypocrisy.

the Messenger of Allaah (peace and blessings of Allaah be upon him) said: "When a person's child dies, Allaah says to His angels, 'You have taken the child of My slave.' They say, 'Yes.' He says, 'You have taken the apple of his eye.' They say, 'Yes.' He says, 'What did My slave say?' They say, 'He praised you and said "Innaa lillaahi wa inna ilayhi raaji'oon (Verily to Allaah we belong and unto Him is our return).' Allaah says, 'Build for My slave a house in Paradise and call it the house of praise.'"

(Classed as hasan by al-Albaani in al-Silsilah al-Saheehah, 1408)