The Hadeeth About Saying “Allahumma ajirni min al-nar” Seven Times
This hadeeth (prophetic narration) was narrated by al-Imam Ahmad in al-Musnad, 17362, and by Abu Dawood, 5079. The hadeeth is as follows:
It was narrated that the Prophet (peace and blessings of Allah be upon him) said: “When you pray Fajr, then say before speaking to any of the people, ‘Allahumma ajirni min al-nar (O Allah, protect me from the Fire)’ seven times. Then if you die on that day, Allah will grant you protection from the Fire. And when you pray Maghrib, then say before speaking to any of the people, ‘Allahumma inni as’aluka al-jannah, Allahumma ajirni min al-nar (O Allah, I ask You for Paradise, O Allah, protect me from the Fire)’ seven times. Then if you die that night, Allah will grant you protection from the Fire.”
Two things may be noted about the hadeeth.
1. It does not say that this du’a (supplication) is to be said after ‘Isha (night prayer), as mentioned in the question.
2. The hadeeth is not saheeh (authentic) in its narration from the Prophet (peace and blessings of Allah be upon him). See al-Silsilah al-Da’eefah by al-Shaykh al-Albani (may Allah have mercy on him), 1624.
Based on this, it is not mustahabb (desirable) to recite this du’a after Fajr and Maghrib prayers.
3. It was narrated that Anas (may Allah be pleased with him) said: The Prophet (peace and blessings of Allah be upon him) said: “Whoever asks Allah for Paradise three times, Paradise will say, ‘O Allah, admit him to Paradise.’ Whoever seeks protection from the Fire three times, Hell will say, ‘O Allah, protect him from the Fire.’”
Narrated by al-Tirmidhi, 2572; Ibn Majah, 4340. This is a saheeh hadeeth; it was classed as saheeh by al-Shaykh al-Albaani (may Allah have mercy on him) in Saheeh al-Jami’, 6275).
But there is nothing to state that this should be recited in conjunction with any particular prayer, or at any particular time.
It is mustahabb for the believer to ask Allah for Paradise a great deal, and to seek protection from Hell a great deal, without saying such words in conjunction with any particular prayer, or at any particular time.
And Allah knows best.
Wister