It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) lifted the curtain while he (peace and blessings be upon him) was in his final illness, and then he (peace and blessings be upon him) said: "O Allah, have I conveyed Your religion?" He (peace and blessings be upon him) said these words three times, then he said: "Nothing remains of the glad tidings of prophethood except true dreams, which a believing servant sees or which are shown to him. Behold! I have been forbidden to recite the Qur'an in bowing and prostration. So when you bow, proclaim the greatness of Allah Almighty, and when you prostrate, supplicate as much as you can in it; your supplication will be answered."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2685
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A person is nearest to his Lord when he is in prostration, so supplicate abundantly in prostration."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2686
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) would recite in his prostrations: 'Allahummaghfir li dhanbi kullahu, diqqahu wa jillahu, wa awwalahu wa akhirahu' (O Allah, forgive me all my sins, the small and the great, the first and the last; forgive them all). In the narration of Ibn al-Sarh there is the addition 'alaniyatahu wa sirrahu', meaning: "and forgive the open sins and the hidden ones too."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2687