Quran in Depth: Al Baqarah 1-20

بسم الله الرحمن الرحيم
In the name of Allah, the Most Gracious, the Most Merciful 


"This is the Book, whereof there is no doubt, a guidance to those who are Al-Muttaqun." 
This is how Surah Al Baqarah opens. Al Baqarah can be translated as The Cow, which is merely a translation of the word Baqarah itself and does not cover the subject of the surah. 
The entire surah is all about guidance, it is an invitation to the Divine Guidance, to Allah (swt), addressed in particular to Jews. The first part, ayaat one to twenty is an introduction to the longest surah in the Quran.

2:3 Who believe in the Ghaib, and perform As-Salat, and spend out of what we have provided for them.

Although there is only guidance in this surah, believers do have to meet a few pre-requisites. These pre-requisites are mentioned in this ayah.
1. Al-Muttaqun - The book is a guidance to those who are Al-Muttaqun, the pious and righteous people who fear Allah (swt). 
2. Believing in the Ghaib - the Ghaib is the unseen, the things that human senses cannot perceive. Allah (swt), Angels, the Revelation, Heaven and Hell, Jinn.
3. Perform As-Salat - To be a believer is to perform salat, to pray.
4. Zakat - A believer should spend his money according to the instructions mentioned in the Quran.

2:4 And who believe in which has been sent down to you and in which were sent down before you and they believe with certainty in the Hereafter.

In this ayah the last pre-requisites are mentioned. 
5. Believe in the Books - A believer should believe in which has been sent down (the Quran) and which has been sent down before (Taurat and Injeel). If you do not believe in the guidance of Allah (swt) cannot benefit the guidance of Allah (swt).
6. Believe in the Hereafter - Without belief in the Hereafter (humans are accountable for all their deeds, this dunya is not everlasting, the Resurrection is true as are Paradise and Hell and lastly being successful at Allah's final judgement is most important) one cannot believe in Islam. 

2:5 They are on guidance from their Lord, and they are the successful.

If you meet the pre-requisites mentioned above, you receive the guidance from Allah (swt) and if you follow His guidance you will be successful.

2:6 Verily, those who disbelieve, it is the same to them whether you warn them or do not warn them, they will not believe. 2:7  Allah has set a seal on their hearts and on their hearings, and on their eyes there is a covering. Theirs will be a great torment.

The people covered by "those who disbelieve" are those who don't believe and don't want to fulfil the pre-requisites. They will not believe because of the Law of Nature, which I explain here.

2:8 And of mankind, there are some who say: "We believe in Allah and in the Last Day" while in fact they believe not.  2:9  They (think to) deceive Allah and those who believe, while they only deceive themselves, and perceive not.  2:10  In their hearts is a disease and Allah has increased their disease. A painful torment is theirs because they used to tell lies. 

These people who think they can deceive Allah (swt) and the believers are hypocrites who don't realise that their deception is only temporary. Allah (swt) knows what is in our hearts and no person is able to deceive everyone for a long period of time. Once it comes out, the deceiver will lose his honour. 
The hypocrisy is a disease in their hearts, and when they think that their deception is successful they will become even more hypocrite, so their disease increases. 

2:11 And when it is said to them: "Make not mischief on the earth," they say: "We are only peacemakers."  2:12 Verily! They are the ones who make mischief, but they perceive not.  2:13 And when it is said to them: "Believe as the people have believed," they say: "Shall we believe as the fools have believed?" Verily, they are the fools, but they know not.  2:14 And when they meet those who believe, they say: "We believe," but when they are alone with their Shayatin, they say: "Truly, we are with you; verily, we were but mocking."  2:15 Allah mocks at them and gives them increase in their wrong-doings to wander blindly.  2:16 These are they who have purchases error for guidance, so their commerce was profitless. And they were not guided.

The hypocrites don't realise that they are in the wrong, they don't realise that Allah (swt) has revealed the Truth. They think that the believers are fools for believing in the Truth, but they will come out fools themselves on the Day of Judgement. 
The Shayatin mentioned in the Quran usually are jinn devils, but here is meant the key people who oppose Islam. This word is used to describe their evil, devilish personality. 

2:17 Their likeness is as the likeness of one who kindled a fire; then, when it lighted all around him, Allah took away their light and left them in darkness. So they could not see.  2:18 They are deaf, dumb, and blind, so they return not.  2:19 Or like a rainstorm from the sky, wherein is darkness, thunder, and lightning. They thrust their fingers in their ears to keep out the stunning thunderclap for fear of death. But Allah ever encompasses the disbelievers.  2:20 The lightning almost snatches away their sight, whenever it flashes for them, they walk therein, and when darkness covers them, they stand still. And if Allah willed, He could have taken away their hearing and their sight. Certainly, Allah has power over all things.

They are deaf to hear the Truth, dumb to speak the Truth and blind to see the Truth. In ayaat 19 and 20 a parable is used. The rainstorm is Islam which came as a blessing. Darkness, thunder and lightning are the threatening dangers and difficulties from the opponents of Islam. When the situation eased, they moved towards Islam, but when the difficulties appeared they stood still. 

I hope this explanation was clear enough and if you think I missed anything or misinterpreted things, please let me know. 

 
May peace, mercy and blessings from Allah be upon you