So it is due
فحق
It is obligatory upon us all
The word of our Lord
قول ربنا
It is due upon us, meaning it is established and obligatory and has become a right in which there is no injustice or falsehood
The word of our Lord
قول ربنا
meaning that everyone who departs from the obedience of Allah and lies about His verses is in the Fire, and His saying
The word of our Lord
قول ربنا
with the punishment, meaning His saying
I will surely fill Hell with jinn and men all together."
لأملأن جهنم من الجنة والناس أجمعين [Hud 11:119]
This, according to what the author said, is what is intended by their saying "the word of our Lord," and it seems he is referring to the saying of the Exalted
But the word of your Lord is to be fulfilled that, "I will surely fill Hell with jinn and men all together."
وتمت كلمت ربك لأملأن جهنم من الجنة والناس أجمعين [Hud 11:119]
But the apparent meaning of the word of Allah referred to is His saying to Iblis
Whoever follows you among them - I will surely fill Hell with you, all together."
لمن تبعك منهم لأملأن جهنم منكم أجمعين [Al-A'raf 7:18]
because the verse the author referred to contains an explanation that Allah, Glorified and Exalted is He, decreed by His wisdom to fill the Fire with the disbelievers, but it does not contain the address directed to Satan and his followers
Whoever follows you among them - I will surely fill Hell with you, all together."
لمن تبعك منهم لأملأن جهنم منكم أجمعين [Al-A'raf 7:18]
So this one, which contains the direct threat to whoever followed Satan, makes interpreting "our word" with the second verse more appropriate than interpreting it with what the author said. Then he said
We are indeed going to taste
إنا لذائقون
We are all indeed going to taste the punishment by that word, and from it arose their saying
So we led you astray
فأغويناكم
justified by his saying
indeed, we were deviators."
إنا كنا غاوين [As-Saffat 37:32]
He says
So the word of our Lord has come into effect upon us
فحق علينا قول ربنا [As-Saffat 37:31]
Upon us, the pronoun refers to the followers and the followed. We are indeed going to taste, the pronoun also refers to the followers and the followed. As if they are saying, "We did not save ourselves, so how can we save you?" Then he said
So we led you astray
فأغويناكم
meaning we made you among the people of error by turning you away from the path of guidance
indeed, we were deviators."
إنا كنا غاوين [As-Saffat 37:32]
This is a justification for his saying
So we led you astray
فأغويناكم
And here you have "justified by his saying," meaning by the saying of the Exalted. It is also correct to say "justified by their saying," meaning by the saying of these people that Allah reported from them. So the indefiniteness of the pronoun has a basis, meaning its singularity and its plurality have a basis.