Interpretation of Kitab At-Tauhid - Ghayatul-Murid (The Destination of the Seeker of Truth)
By the Noble Shaikh: Salih bin 'Abdul-'Aziz bin Muhammad bin Ibraheem Aali Shaikh
Here is a sample chapter from the book without Arabic verses. Due to the OCR there may be some typographical errors.
Chapter 1: The Virtue of At-Tauhid and what Sins it Expiates*
Allah the Most High said,
"Those who believe and do not mix their belief with any Dhulm, for them there is security and they are guided ones." (6:82) 
'Ubaadah bin As-Saamit (R) narrated that Allah's Messenger; said,
"Whoever testifies that there is none worthy of being worshipped but Allah, Who has no partner, and that Muhammad is His slave and Messenger, and that 'Eesa (Jesus) is the Slave of Allah, His Messenger, and His Word which He bestowed in Maryam (Mary) and a spirit (created) from Him, and that Paradise is true, and that the Fire is true, Allah will admit him into Paradise, whatever his deeds may be. 
They (Al-Bukhari and Muslim) both recorded this Hadith. They (Al-Bukhari and Muslim) also recorded the Hadith of 'Itbaan:
"Indeed Allah has forbidden for Hell the person who says: 'There is nothing worthy of being worshipped but Allah,' seeking thereby the Face of Allah." 
Abu Sa'eed AI-Khudri narrated that Allah's Messenger said,
"Musa (Moses) said: 'O my Lord, teach me something by which I can remember You and supplicate to You.' Allah answered: 'Say, O Musa, La ilaha illallah (none has the right to be worshipped but Allah).' Musa said: 'O my Lord, all your slaves say this.' Allah said: 'O Musa, if the seven heavens and all of their inhabitants besides Me, and the seven earths were in a pan (of a scale), and La ilaha illallah was in (another) pan, La ilaha illallah would outweigh them."
Ibn Hibbaan and AI-Haakim recorded this, and he (AIHaakim) graded it authentic (Saheeh).
At-Tirmithi recorded a Hadith that he graded good (Hasan), from Anas (who said): "I heard Allah's Messenger' ; saying,
"Allah the Most High said, "O son of Aadam! If you came to Me with sins filling the earth, then you met Me without associating anything with Me, I would come to you with its (the earth's) fill of forgiveness.'" 
Important issues of the Chapter
1) The abundance of AI lah's favor.
2) The numerous rewards of At-Tauhid with Allah.
3) Along with this it expiates sins.
4) Explanation of the verse which is in Surah AI An'am (6:82).
5) Notice the five points in the Hadith of 'Ubaadah.
6) That when you combine it (the Hadith of 'Ubaadah) with the Hadith of 'Itbaan and that which follows it, the meaning of the statement La ilaha illallah becomes clear to you, and the mistake of those who have been deceived also becomes clear to you.
7) Drawing attention to the condition which is in the Hadith of 'Itbaan.
8) The fact that the Prophets needed to be made aware of the virtue of La ilaha illallah.
9) Drawing attention to its (the statement La ilaha illallah) outweighing all of creation, along with the fact that many of those who say it lighten its weight in the scale.
10) The text which proves that the earths are seven just as the heavens (are seven).
11) That they have inhabitants.
12) Confirmation of the attributes, contrary to (the understanding of) the Ash'ariyyah.
13) That if you know the Hadith of Anas, then you know that strong the Prophet's statement in the Hadith of 'Itbaan,
"Indeed Allah has forbidden for Hell the person who says, 'none has the right to be worshipped but Allah,' seeking thereby the Face of Allah,"
that it is by abandoning Ash-Shirk, not simply saying it with the tongue.
14) Notice the combined mentioning of both Isa (Jesus) and Muhammad as two Slaves of Allah and His Messengers.
15) Knowing that Isa was particularly as being the Word of Allah.
16) Knowing that he ('Isa Alay hes salam) was a spirit from Him (Allah).
17) Knowing the virtue of belief in Paradise and the Fire.
18) Knowing his (the Prophet's) statement, "...whatever his deeds may be."
19) Knowing the AI-Meezaan (scale) has two pans.
20) Knowing the usage of the term "Face" (of Allah).
* This means its expiation of sins. Thus, the more the slave increases in the actualization of At-Tauhid, the more he is likely to enter Paradise, whatever his deeds may be. For this reason the Imaam - may Allah have mercy upon him - mentioned the Verse of Surah AI-An'am (6:82).
 And Allah the Most High said,
"Those who believe and do not mix their belief with Zulm, for them there is security and they are guided ones." (6:82)
The word Zulm (wrongdoing, oppression) here means Ash-Shirk. This is like what has been narrated in the Hadith of Ibn Mas'ud that the Prophet said concerning this Verse when the Companions considered it to be something tremendous (i.e. too difficult). They said, "O Messenger of Allah! Which of us does not wrong himself (i.e. by committing sins)?!" The Prophet (S) replied,
"It is not that which you think. The Zulm is As-Shirk. Don't you hear the statement of the righteous slave (Lugmaan), 'Verily Ash-Shirk (associating partners with Allah) is a great Zulm (wrongdoing, oppression and injustice) indeed."' (31:13)
Thus, the meaning of the Verse according to what is appropriate for this chapter is: Those who believe and do not mix their faith up with any Shirk; for them there is security and they are guided ones. Thus, the virtue of the one who believes - meaning he singles out Allah with At-Tauhid, and he does not mix his faith up with any Dhulm, meaning he does not mix his belief in At-Tauhid up with any Shirk - is that for him is complete security and guidance. Hence, the more At-Tauhid is decreased by the servant being covered with some types of Dhulm, which is Ash-Shirk, the more the security and guidance leaves him in relative proportion to that.
 He then said: 'Ubaadah bin As-Saamit (R) narrated that Allah's Messenger (S) said,
"Whoever testifies that there is none worthy of being worshipped but Allah, Who has no partner, and that Muhammad is His slave and Messenger..."
until he said: "Whatever his deeds may be."
This means, even if he was deficient in his deeds and he had sins and acts of disobedience. This is from the bounty of At-Tauhid upon its people.
 He then said: They (Al-Bukhari and Muslim) also recorded the Hadith of 'Itbaan:
"Indeed Allah has forbidden for Hell the person who says: 'There is nothing worthy of being worshipped but Allah,' seeking thereby the Face of Allah."
When a person says this statement, which is the statement of At-Tauhid, seeking the Face of Allah by it, and he comes with its conditions and its requirements, Allah favors him and gives him what He has promised him of making him forbidden for the Fire. And this is a great bounty and favor. However, whoever comes with At-Tauhid and abstained from that which contradicts it, yet he had some sins and acts of disobedience, and he died without repenting, then he is under the Will of Allah. If Allah wills, He will punish him, then - after some time - He will make the Fire forbidden for him, and if He wills, He will forgive him and make the Fire forbidden for him initially (without punishment).
 Abu Sa'eed AI-Khudree narrated that Allah's Messenger (S) said,
"Moosaa (Moses) said: 'O my Lord, teach me something by which I can remember You and supplicate to You.' Allah answered: 'Say, O Moosaa, La ilaha illallah (non has the wright to be worshipped but Allah)..."
This means that if it is imagined that the sins of the servant reached the weight of the seven heavens and the weight of all that they contain of slaves and angels, and the weight of the earth, the statement Lailaha illallah would outweigh that weight of sins. This is the great virtue of the statement of At-Tauhid and it is only for whoever the statement becomes strong in his heart. Therefore, he becomes sincere in it and a firm believer in it, having no doubts concerning what it implies. He believes in what it contains and he loves what it implies. Thus, its effect becomes strong in the heart and it enlightens it, and as long as it is like this, it burns (away) whatever it meets of sins.