التفسير التبليغي
(وَالطَّيْرَ مَحْشُورَةً كُلٌّ لَهُ أَوَّابٌ) (19)
(وَالطَّيْرَ مَحْشُورَةً) He expressed the collectiveness as if it were a single entity... This is how the people of migration and travel are, moving between the regions of the inhabited world.
Among the objectives of effort is the social gathering of hearts.
The birds would gather for him and glorify Allah.
The mountains were mentioned before the birds because their subjugation and glorification are more astonishing and more indicative of power than that of birds, for they are inanimate, while birds are animals, though not speaking.
They were obedient to him in the path of upholding truth and abolishing falsehood.
Then He said (مَحْشُورَةً), and birds, as we know, are more averse to humans... And in this, there is a sign for those striving for Allah's religion not to despair of creation despite their strong aversion... Are they like mountains in their firmness, or like birds in their aversion, impulsiveness, and lightness...!!
(وَالطَّيْرَ مَحْشُورَةً)
Whoever was able to do this is more capable of gathering those who are less averse than birds, and in this, there is an indication of the Resurrection and the Great Gathering.
(كُلٌّ لَهُ أَوَّابٌ) Whenever you finish being preoccupied with creation, you must immediately turn to glorifying the Truth.
(وَالطَّيْرَ مَحْشُورَةً كُلٌّ لَهُ أَوَّابٌ) This is a sign to the Prophet (peace be upon him) that whenever We wish, We can make your people with you in subjugation like this, so do not despair of them despite their strong aversion, for We made them so that you may discipline yourself through them, and increase in majesty, elevation, prominence, and perfection through patience with them, in addition to other wisdoms that minds cannot encompass.
Do not despair of their softening towards you and their return to you, for they are no more than mountains in strength and firmness, or birds in aversion, impulsiveness, and lightness. So, whenever We wish, We can make them for you like We made the mountains and birds with David (peace be upon him); rather, their matter is easier and their affair is less difficult.
(كُلٌّ) meaning every single one of the mountains and birds (لَهُ أَوَّابٌ) meaning returning [to Him/obedient].
Source: التفسير التبليغي