The Surah Al-Baqarah is referred to by this name because the story of the cow of the Israelites in verses of 67 to 71 is repeated several times. (وَ إِذْ قالَ مُوسى لِقَوْمِهِ إِنَّ اللَّهَ یَأْمُرُکُمْ أَنْ تَذْبَحُوا بَقَرَةً قالُوا أَ تَتَّخِذُنا هُزُواً قالَ أَعُوذُ بِاللَّهِ أَنْ أَکُونَ مِنَ الْجاهِلین)When Moses said to his nation: 'Allah commands you to slaughter a cow, ' they replied: 'Are you taking us in mockery? ' 'I seek protection with Allah lest I should be one of the ignorant' he said. And given that this issue is of great importance in human growth and development and so on, it has been named Surah Al-Baqarah.
source : erfan.ir