Allah, exalted be His praise, says: "Except the weak among the men, women and children who are unable to devise a plan and cannot find a way (out) - for those, it is hoped that Allah will pardon them, and Allah is ever Pardoning, Forgiving." [Surah al-Nisa: 98-99]
Imam al-Shafi'i (may Allah have mercy on him) said: "It is said that the word 'asa' (it is hoped) from Allah Almighty is certain (and binding)."
Sayyiduna Ibn Abbas (may Allah be pleased with them both) says: Every 'asa' (it may be) used in the Noble Qur'an is used in the sense of something certain (wajib).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17753