Hadith: Allāuhumma inni a‘ūdhu bika min ‘adhāb al-qabr, wa min ‘adhāb an-nār, wa min fitnat al-mahya wa al-mamāt, wa min fitnat al-masīh ad-dajjāl

عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ:
كَانَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ يَدْعُو وَيَقُولُ: «اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنْ عَذَابِ القَبْرِ، وَمِنْ عَذَابِ النَّارِ، وَمِنْ فِتْنَةِ المَحْيَا وَالمَمَاتِ، وَمِنْ فِتْنَةِ المَسِيحِ الدَّجَّالِ». وفِي لَفْظٍ لِمُسْلِمٍ: «إِذَا فَرَغَ أَحَدُكُمْ مِنَ التَّشَهُّدِ الْآخِرِ، فَلْيَتَعَوَّذْ بِاللهِ مِنْ أَرْبَعٍ: مِنْ عَذَابِ جَهَنَّمَ، وَمِنْ عَذَابِ الْقَبْرِ، وَمِنْ فِتْنَةِ الْمَحْيَا وَالْمَمَاتِ، وَمِنْ شَرِّ الْمَسِيحِ الدَّجَّالِ».
[صحيح] - [متفق عليه] - [صحيح البخاري: 1377]

Abu Hurayrah (may Allah be pleased with him) reported:
The Messenger of Allah (may Allah's peace and blessings be upon him) used to say the following supplication: "Allāuhumma inni a‘ūdhu bika min ‘adhāb al-qabr, wa min ‘adhāb an-nār, wa min fitnat al-mahya wa al-mamāt, wa min fitnat al-masīh ad-dajjāl (O Allah, I seek refuge with You from the punishment of the grave, the punishment of the Fire, the trials of life and death, and the trial of the Dajjāl (Antichrist)." A wording of Muslim reads: "When any of you completes the last Tashahhud, let him seek refuge with Allah from four things: the punishment of Hellfire, the punishment of the grave, the trials of life and death, and the evil of the Antichrist."
[Authentic hadith] - [Narrated by Bukhari & Muslim] - [Sahih Bukhari - 1377]

Explanation

The Prophet (may Allah's peace and blessings be upon him) used to seek refuge with Allah from four things after reciting the last Tashahhud and before ending the prayer, and he commanded us to do the same.
First: from the punishment of the grave.
Second: from the punishment of Hellfire on the Day of Judgment.
Third: from the trials of life, including its forbidden desires and its misleading doubts, and from the trials of death, i.e., the time of dying, including deviation from Islam or from the Sunnah, or the trial of the grave like the questioning of the two angels.
Fourth: from the trial of the Antichrist who will come at the end of time as an affliction from Allah to test His slaves. The Antichrist was mentioned in particular because of the gravity of his trial and misguidance.