Allaah سبحانه و تعالى says,
"(This is) a Book (the Qur'aan) which We have sent down to you, full of blessings that they may ponder over (liyaddabbaroo) its Verses, and that men of understanding may remember." (Soorah Saad, 38:29)
Imaam Muhammad Ibn al-Husayn al-Aajurree رحمه الله said,
"Do you not see, may Allaah have mercy upon you, how your Noble Master سبحانه و تعالى encourages His creation to contemplate His words, and those who contemplate His words know the Lord, the All-Mighty, the Venerable, and know the greatness of His Authority and Power, and know the greatness of His favour upon the believers, and know what is obligatory of worship upon them, and he is wary from that which his Noble Master سبحانه و تعالى has warned him, he seeks that which He impels him with, and whoever has this characteristic when he recites the Qur'aan and listens to others reading it, then it becomes a healing for him; he is wealthy without wealth, he has strength without a tribe, he is affable with that which others are averse to.
When he begins to recite a chapter of the Qur'aan his concern is,'When can I act upon the admonition that I am reading?' His intention is not 'when will I complete this chapter,' but rather his intent is only 'when will I comprehend the address from Allaah سبحانه و تعالى? When will I submit? When will I ponder?' Because his recitation of the Qur'aan is worship and worship is not done heedlessly. And Allaah سبحانه و تعالى is the granter of success." 
Shaykh Muhammad 'Umar Baazmool said,
"Take note here that the objective of contemplation is not just the thought process or recitation, (but also) the effect becoming apparent in the heart by an increase of faith and what results from that of righteous actions of the limbs.
Regarding the statement of Allaah سبحانه و تعالى:
"...recite it as it should be recited." (Sooratul-Baqarah, 2:121)
Imaam Mujaahid رحمه الله said, 'They act upon it as it should be acted upon.'
Ummul-Mu'mineen Aa'ishah رضي الله عنها was asked about the statement of Allaah سبحانه و تعالى:
"And verily, you (O Muhammad صلى الله عليه وسلم) are on an exalted standard of character." (Sooratul-Qalam, 68:4)
'What was the character of the Messenger of Allaah صلى الله عليه وسلم?' She replied, 'His character was the Qur'aan.' 
Sayyiduna Hudhayfah رضي الله عنه said, 'Oh group of reciters! Follow the straight path, for then you have taken a great lead. But if you divert left or right, then you will go far astray.' 
Sayyiduna 'Alee Ibn Abee Taalib رضي الله عنه said, 'Oh carriers of the Qur'aan (or oh carriers of knowledge)! Act on it, as the scholar is the one that acts on what he knows and his knowledge corresponds to his actions. There will be a people who carry knowledge but it doesn't pass their throats. Their actions do not correspond to their knowledge, and their actions in private differ from their actions in public. They sit in circles of knowledge and show off amongst one another, to the point that they become angry with their companion if he sits with someone else and leaves him. Those are the one whose actions in those sittings won't raise up to Allaah, the Most High.' 
Imaam Hasan al-Basri رحمه الله said, 'This Qur'aan was read by slaves and children without having knowledge of its interpretation nor did they contemplate it, they only followed it. That does not happen by simply remembering its words and ignoring its meanings. And some of them will say, "I've reade the Qur'aan and didn't leave out a single letter." But, by Allaah, he has left it all out, every letter of it, because the Qur'aan is not seen in support of him, in terms of his manners and actions. This is clear to the extent that some of them even say: "I read this chapter of the Qur'aan in just one breath." These people are truly neither reciters, nor scholars, nor wise, nor devout. They are people not acting on what they read. When were reciters ever like this? May Allaah سبحانه و تعالى learn their like among men.' 
Imaam Hasan al-Basri رحمه الله also said, 'The people were commanded to act on the Qur'aan, then they took its recitation as action.'"  
 Akhlaaq Hamla al-Qur'aan.
 Saheeh Muslim.
 Saheeh al-Bukhaaree.
 at-Tibyaan fee Adab Hamla al-Qur'aan.
 Sunan Sa'eed Ibn Mansoor (2/420); Sunan al-Bayhaqi (2/541); Imaam Ibnul-Mubaarak رحمه الله: az-Zuhd (1/276).
 Tafseer as-Sam'aanee (4/119); Madaarijus-Saalikeen (1/451); Talbees Ibless (p. 109).
 Contemplation Of The Qur'an & Its Effect Regarding Purification Of The Soul, pp. 7-8 and pp.32-33.