Tafsir of Al-Jathiyah 45:28

(And you will see every nation) from among the gathered nations (kneeling), sitting upon their knees, prepared to spring up, which is the posture of a guilty, fearful person awaiting that which he dislikes. Ibn Abbas narrated that "kneeling" means gathered together. Qatadah stated it means groups, derived from al-juthwah (with the jim carrying any of the three vowel points), which is a group gathered upon a mound, meaning accumulated earth. Mu’arrij al-Sadusi said it means submissive, in the dialect of Quraysh.

The address in "(You) will see" is directed to whoever is capable of seeing, or to the master of those addressed, peace and blessings be upon him. It is a visual sight, and "kneeling" is a state (hal). It is permissible for it to be an adjective; if the verb "see" were intended as mental perception, it would be a second object. It has been recited as jathiyah with a dhal, and jadhu is more indicative of being prepared to spring up than jathu, because the jadhi is one who sits upon his toes. It is also possible that jadhi is synonymous with jathi, where the tha has been replaced with a dhal, as the tha and dhal are closely related, as in the words shahath and shadhah (beggar).

(Every nation will be called to its book), to the record of its deeds which the recording angels wrote, so that it may be reckoned. It is singular because it refers to the genus; otherwise, every individual from every nation has a record containing their deeds. It has been said: the intention is to be called to the Book (the Scripture) to see whether it acted according to it or not. This was narrated from Yahya ibn Sallam, though he restricted "every nation" to every disbelieving nation, whereas the apparent meaning is general. Others have said the intent is the Preserved Tablet, meaning they are called to that which was previously written for them therein.

Ya’qub recited "every" in the accusative case (kulla), which is interpreted as being a substitute for the first "every." The clause "(will be) called" is an adjective. The substitution of the nation called to its book for the nation that is kneeling is good, and this comes from the description. The same is said regarding whether the clause is a state (hal). If the seeing is mental perception and the clause "(will be) called" is a second object, then the apparent interpretation is that it is an emphasis. Making it an emphasis while the clause is an adjective results in an intrusion of emphasis between two adjectives, which, as stated in al-Kashf, is not considered elegant.

(Today you are being recompensed for what you used to do) is the content of a hidden declaration. It is a state or a predicate following a predicate. There is a hidden genitive construction in the speech, meaning: the recompense for what you used to do, etc. Or, it is metaphorical.