The reason for Al Baqarah’s revelation was to teach the mukmin (believers) how to lead mankind after hijrah (migration from Makkah to Madinah). Among the themes are guidance, taqwa (faith), belief, sacrifices and knowledge.
One of the main theme of this chapter is guidance/ covenant.
Whoever accepts the guidance and adhere to the covenant will gain leadership of mankind e.g. Adam, Ibrahim (Abraham), Dawud (David) etc. This happened to the Muslim after hijrah.
To adhere to the covenant, one must have taqwa, belief in the unseen, etc.
Some people pretended to hold onto it i.e. munafiq (hypocrites). Some prefers chaos and corruptions i.e. fasiq (disobedients, miscreants). Some rejected it ie kuffar (disbelievers).
The instruction to change qiblah (direction in prayers) signifies the change of leadership from Jews to Muslim.
Also included in this surah are the details of muslim covenant (eg jihad, riba, fast etc), parables, etc.
Al Baqarah‘s Virtues
House which al Baqarah was recited in it wont be harmed by devils (Hadith from Tirmizi, An Nasaie, Hakim, Ad Darimi, At Tabrani, Ibn Hibban).
Al Baqarah and Ali Imran will intercede for their people during reckoning (Ibn Majah, Muslim, Ahmad).
Contains basic concepts and many rulings. Rasulullah once appointed a younger commander because he remembers and practise Al Baqarah.
Fully madani (revealed after hijrah ie migration), among first to be sent down after hijrah and last revealed ayat. Also said that most are madani, some are makki (revealed before hijrah).
Also the longest surah.