Allah (Subhaanahu Wa Ta’aalaa) has given every single Prophet, one request – one supplication — that is guaranteed to be accepted. The Prophets of the past have used this to ask something that they really wanted to see fulfilled. Some Prophets used this to protect the Believers from their enemies present in their own nation. For example, Hadhrat Nooh (Noah) after preaching for nine hundred and fifty years, asked his Lord, Allah (Subhaanahu Wa Ta’aalaa) to protect the Believers because the Infidels were still not listening to his message and supplicated:
رَبِّ لَا تَذَرْ عَلَى الْأَرْضِ مِنَ الْكَافِرِينَ دَيَّارًا [نوح: 26]
“My Lord! Do not leave on earth even a single inhabitant (surviving) out of the disbelievers.” (Nooh 71:26)
Thereafter, Allah (Subhaanahu Wa Ta’aalaa) destroyed his city, which was all of humanity at that time.
Similarly Hadhrat Ibrahim (Abraham) made a supplication to Allah (Subhaanahu Wa Ta’aalaa) for the Prophet Muhammad (SallAllaho Alaihe WaSallam), asking for the Messenger to come from his progeny. That is why Prophet Muhamamd (SallAllaho Alaihe WaSallam) later said: “I’m the Du’aa of my father Ibrahim.”
Hadhrat Sulaiman made supplication to Allah (Subhaanahu Wa Ta’aalaa):
قَالَ رَبِّ اغْفِرْ لِي وَهَبْ لِي مُلْكًا لَا يَنْبَغِي لِأَحَدٍ مِنْ بَعْدِي [ص: 35]
“…….Bless me with a kingdom that will not be available to anyone after me.”
So Allah (Subhaanahu Wa Ta’aalaa) gave him power that no one had before him.
The Prophet Hadhrat Muhammad (SallAllaho Alaihe WaSallam) had the greatest of the supplications and what did he use it for? The Prophet (SallAllaho Alaihe WaSallam) said that Allah (Subhaanahu Wa Ta’aalaa) has given one Du’aa to every single Prophet and every single Messenger, that he has guaranteed that he will respond to. And every single Prophet has used up this Du’aa in this world, except for me. I have saved it and I have not used it and I will not use it in this life. I have kept it for my Ummah and I will use it for them on the Day of Judgment. And my Du’aa will be: “O Allah! Forgive my entire Ummah.
This is the Dua of the Prophet (SallAll-aho Alaihe WaSallam), that anybody who believed in him, O Allah! Forgive him. Allah (Subhaanahu Wa Ta’aalaa) will accept this Du’aa and every single Muslim will eventually enter Jannah. Every single person who believed in him and acted upon it even a little bit, no matter how sinful that person is, will eventually enter Jannah.
So here we see, how the Prophet (SallAllaho Alaihe WaSallam) saved this one Du’aa for us.