Prayer is of great significance in Islam, and its importance makes adhering to it one of the most binding of the obligatory duties in Islam, for it is the foundation of faith. The expiation for the one who forgets a prayer is to offer the prayer when he remembers it. This is because of its great importance, virtue and significance in Islamic teachings. In this hadith, the Prophet (blessings and peace of Allah be upon him) says: “Whoever forgets a prayer, let him pray when he remembers it.” In other words: whoever forgets to offer any prayer until the time for it ends, let him hasten to make it up as soon as he remembers it, for there is no expiation or pardon for the sin of missing it, even if that was due to forgetfulness, except offering the prayer when he remembers it, as Allah says in His holy Book: {and establish prayer when you remember it} [Ta-Ha 20:14]. That is, establish prayer when you remember a forgotten prayer and when you recall that you owe a prayer, whether that is still within the time for that prayer or not, so that you will remember Me in prayer by glorifying and venerating Me, and I will remember you by praising and commending you. This hadith highlights the importance of prayer and emphasizes that one should not be heedless about doing it..