Their repentance from this crime- as Allah the Almighty made it- was that those who did not worship the calf would kill the ones who worshipped it. The scholars of the interpretation of the Noble Quran mentioned that 70,000 of the calf worshippers were killed, and Allah forgave them and accepted their repentance.
Allah, Exalted and Sublime be He, wanted the notables of the Children of Israel to come out to meet Him, so that they would apologize for what the worshippers of the calf had done.
The reason that their repentance was the above-mentioned. was because the crime was grave and heinous. The calf was made by a human being whom they could see, it made an ugly sound they could hear; like the sound of the cow, and it brought them no benefit. Yet, they made it the Lord, Exalted and Sublime be He. Not to mention, they accused Moses of being forgetful, “This is your god and the god of Moses, but Moses forgot ˹where it was˺!” They claimed that although they knew that Moses went to meet Allah, Exalted and Sublime be He.
جعل الله توبتهم من هذه الجريمة أن يقتل من لم يعبد العجل من عبدَه، -ذكر المفسرون أنهم قتلوا منهم سبعين ألفاً- وقد تاب الله عليهم وقبل توبتهم
أراد الله عز وجل أن يخرج وجهاء بني إسرائيل للقاء الله عز وجل ليعتذر الوجهاء عما صنع قومهم من عبادتهم للعجل
وإنما كانت هذه هي التوبة؛ لأن الجريمة كانت شنيعة فالعجل من صنع آدمي يرونه بأعينهم، وهم يسمعون صوته القبيح-له خوار- ويرون ألا نفع فيه، ومع ذلك جعلوه هو الرب-تعالى الله وتقدس-، بل إنهم نسبوا لموسى الذهول والنسيان، “هذا إلهكم وإله موسى فنسي“، مع أنهم يعلمون أن موسى ذهب للقاء الله-تعالى الله وتقدس