Abdullah ibn Masud –Allah be well-pleased with him- narrates:

“One day the Messenger of Allah –upon him blessings and peace- asked me, ‘Can you read to me some portion of the Quran?’‘ How can I read you some Quran when it is you to whom the Quran is revealed?’ I responded.

‘I like hearing the Quran from others, too’ said the Messenger of Allah (pboh). Thereupon I began reciting surah an-Nisa.  When I came to the ayah that says: 

فَكَيْفَ إِذَا جِئْنَا مِن كُلِّ أمَّةٍ بِشَهِيدٍ وَجِئْنَا بِكَ عَلَى هَـؤُلاء شَهِيدًا

‘How will it be, then, when We bring from every people a witness and bring you as a witness against these?’ (Sura an-Nisa, ayah 41), he (pboh) said:

‘That will suffice for now...’

When I fixed my eyes on him, I saw tears flowing freely from both his eyes.” (Bukhari, Tafsir, 4/9; Muslim, Musafirin, 247)

Aisha –Allah be well-pleased with her- recounts a scene that provides a glimpse of the Prophet’s (pboh) sensitivity of heart and depth of contemplation:

“One night, the Messenger of Allah –upon him blessings and peace- said to me, ‘If you allow me, Aisha, I wish to spend the night worshiping my Lord.’

‘I would surely love to be with you’, I said, ‘but I would love even more anything that makes you happy.’

He, The Messenger of Allah (pboh) then got up, completed his ablutions and began his salat. He was crying...So much so that the tears soaked his clothes, beard and even the ground on which he fell prostrate. Still in that condition, Bilal came to call him to fajr salat. Seeing him overflowing with tears, Bilal wondered:

‘Why do you cry, Messenger of Allah, when Allah has forgiven your past and future sins ?’ 

‘Shouldn’t I be a thankful servant to his Lord?’ replied he. ‘Such ayat were revealed to me this evening that would place shame on him who reads them without contemplating its meaning.’ He then disclosed the revelation: 

إِنَّ فِي خَلْقِ السَّمَاوَاتِ وَالأَرْضِ وَاخْتِلاَفِ اللَّيْلِ وَالنَّهَارِ لآيَاتٍ لِّأُوْلِي الألْبَابِ

الَّذِينَ يَذْكُرُونَ اللّهَ قِيَامًا وَقُعُودًا وَعَلَىَ جُنُوبِهِمْ وَيَتَفَكَّرُونَ فِي خَلْقِ السَّمَاوَاتِ وَالأَرْضِ رَبَّنَا مَا خَلَقْتَ

هَذا بَاطِلاً سُبْحَانَكَ فَقِنَا عَذَابَ النَّارِ

‘Most surely in the creation of the heavens and the earth and the alternation of the night and the day there are signs for men who understand. Those who remember Allah standing and sitting and lying on their sides and reflect on the creation of the heavens and the earth:  "Our Lord!   You have not created this in vain!  Glory be to You; save us then from the chastisement of the fire!" (Sura al Imran, 190-191)