This may be for the fact that Shu‘ayb was originally from...

This may be for the fact that Shu‘ayb was originally from Madyan and he was relative only with the people of that place, not with the people of ’Aykah. That is why when in Surah Hud, No. 11, verse 84 the Qur’an refers to only Madyan, this phrase is used, where it says: “And to (the people of) Madyan (We sent) their brother Shu‘ayb...”, but since the concerning verse speaks about the People of ’Aykah and they had no relation with Shu‘ayb, then this phrase has not been mentioned.

Then he (as) added: “Verily I am unto you a trustworthy messenger.” “Then be in awe of Allah and obey me.” “And I do not ask you any recompense for it, my recompense is only from the Lord of the worlds.” These sentences are the same form of well-calculated sentences which other prophets announced at the beginning of their call.

They are invitation to piety, emphasizing on their background of trustworthiness among people, and saying that their godly call has only spiritual motive and they demand no material wage for it from any one. This was for the sake that the pretext seekers and cynical ones might not misuse it.

“And do not defraud people in their (due) goods, and do not act corruptly in the earth, making mischief.” The act of defrauding is unlawful, and observing the right of people is obligatory, “Fill up the measure...”. The Arabic word /kayl/ (measure) usually is used for liquid substances; the word /qistas/ (balance) is used for weights; and the word /’ašya’/ (goods), in this sense, is used for the things which are counted or bought and sold by the pieces.

In these holy verses, there are two divine enjoinments and two prohibitions which are complementary of each other: (Fill up - and be not), (weight - do not defraud) It is mentioned in some Islamic narrations that the persons who do not tell the blemish or defect of their goods to the customer the angels will curse them, and those who deceive others with guile and plotting are the worst people.