This commentary explains ayahs 7:148–149 together.
Story of worshipping the Calf
Allah describes the misguidance of those who worshipped the calf that As-Samiri made for them from the ornaments they borrowed from the Copts. He made the shape of a calf with these ornaments and threw in it a handful of dust from the trace of the horse that the Angel Jibril was riding, and the calf seemed to moo. This occurred after Musa went for the appointed term with his Lord, where Allah told him about what happened when he was on Mount Tur. Allah said about His Honorable Self,
قَالَ فَإِنَّا قَدْ فَتَنَّا قَوْمَكَ مِن بَعْدِكَ وَأَضَلَّهُمُ السَّامِرِىُّ
((Allah) said: "Verily, We have tried your people in your absence, and As-Samiri has led them astray") 20:85. The scholars of Tafsir have different views over the calf, whether it actually became alive and mooing, or if it remained made of gold, but the air entering it made it appear to be mooing. These are two opinions. Allah knows best. It was reported that when the statue mooed, the Jews started dancing around it and fell into misguidance because they adored it. They said that this, the calf, is your god and the god of Musa, but Musa forgot it! Allah answered them,
أَفَلاَ يَرَوْنَ أَلاَّ يَرْجِعُ إِلَيْهِمْ قَوْلاً وَلاَ يَمْلِكُ لَهُمْ ضَرّاً وَلاَ نَفْعاً
(Did they not see that it could not return them a word (for answer), and that it had neither power to harm them nor to do them good) 20:89. Allah said here,
أَلَمْ يَرَوْاْ أَنَّهُ لاَ يُكَلِّمُهُمْ وَلاَ يَهْدِيهِمْ سَبِيلاً
(Did they not see that it could neither speak to them nor guide them to the way) Allah condemned the Jews for falling into misguidance, worshipping the calf and ignoring the Creator of the heavens and earth, the Lord and King of all things. They worshipped besides Him a statue made in the shape of a calf, that seemed to moo, but it neither spoke to them nor brought them any benefit. Rather, their very sense of reason was blinded because of ignorance and misguidance. Allah's statement,
وَلَمَّا سُقِطَ فَى أَيْدِيهِمْ
(And when they regretted), and felt sorrow for their action,
وَرَأَوْاْ أَنَّهُمْ قَدْ ضَلُّواْ قَالُواْ لَئِن لَّمْ يَرْحَمْنَا رَبُّنَا وَيَغْفِرْ لَنَا لَنَكُونَنَّ مِنَ الْخَـسِرِينَ
(and saw that they had gone astray, they said: "If our Lord have not mercy upon us and forgive us, we will certainly become among the losers.") or among the destroyed ones. This was their recognition of their sin and their way of seeking salvation from Allah the Most Mighty and Majestic.