قالَ اَمیرُالمُوْمِنینَ عَلِیُّ بْنُ اَبیطالب(علیه السلام)
أَلا لا خَيْرَ فى عِلم لَيْسَ فيهِ تَفَهُّمٌ
أَلا لا خَيْرَ فى قَرَائة لَيْسَ فيْها تَدَبُرٌ
أَلا لا خَيْرَ فى عِبادَة لَيْسَ فيْها تَفَكُّرٌ
Imam Ali (‘a) said:
Know that there is no benefit in knowledge without thought!
Know that there is no benefit in the recitation of the Quran if there is no contemplation!
Know that worship without reflection is without effect!
Filling the mind with all sorts of scientific formulas, logical precepts, philosophical principles, and all other types of knowledge is of extremely little value unless it is accompanied with proper thinking and a clear and accurate worldview. If one is not familiar with the principles of life, then all of these things d r o p dramatically in value. Similarly, the effects of reading the Holy Quran become almost insignificant if it is not accompanied with contemplation and attention in to the depths of meaning found within it. Similarly, worship without reflection and the use of the intellect is like a body without a spirit and it lacks the loftier effects that such worship can have.
 UāŪl al-Kāfī, vol. 1, p. 36. This tradition can also be found in Tuḥaf al-ÝUqŪl