Why did Iblees tell Allah all of this? Because he knew that Allah's promise is the truth. When Allah told Iblees he was from those given respite he also knew that Allah doesn't break His promise. How about us when we make du`a' (supplication)? Do we feel that Allah doesn't break His promise to us? Are we as confident in our du`a' as Iblees, who is the enemy of Allah ? How is it possible that Iblees can be more confident in his du`a' than us?
Iblees told Allah his plan:

[Shaytan] said, 

"Because You have put me in error, I will surely sit in wait for them on Your straight path. Then I will come to them from before them and from behind them and on their right and on their left, and You will not find most of them grateful [to You]." (Qur'an 7:16-17)

When Shaytan blamed Allah by saying, "Because You have put me error," this was a mistake in his belief in the qadr (decree) of Allah . If done on purpose, a mistake in `aqidah (belief) is kufr (disbelief in Allah). There's a hadith (record of the words of the Prophet ) that mentions this in Sahih Bukhari:

In the time of Bani Israel (the people of Israel), a man lived with a roommate who didn't pray. When he encouraged his roommate to pray, the roommate just said he didn't feel like praying. The man went back later and tried to encourage his roommate again but received the same response. Finally, the third time the man came to his roommate and said, "If you don't pray, Allah will never forgive you."

The Prophet said that Allah will resurrect these two people and will bring forward the one who didn't pray and ask him, "Why didn't you pray?" The man will say, "Wallahi (I swear by Allah), I loved You but I was weak. I believed in You but I was weak." Allah will say, "I forgive you." Then Allah will bring forward the righteous man who was advising his friend and ask, "Why did you tell him I wouldn't forgive him?" Why does Allah ask him that? Because in our belief anyone who dies believing in Allah and the Prophet as the last Prophet insha'Allah (God willing) will go to Paradise (although some later than others). Allah can forgive any sin except shirk (associating partners with Him) for whomever He wants (Qur'an 4:116); this is part of our `aqidah (belief). We also know that if someone repents from shirk, Allah will forgive it. So, saying that Allah will never forgive someone is a mistake in our belief.

When Iblees said Allah misguided him, this was a mistake in his belief because he attributed misguidance to Allah . We don't find misguidance amongst the names or attributes of Allah . Allah doesn't misguide people; human beings choose to be misguided. Like Allah says in the Qur'an, "...and when they deviated, Allah caused their hearts to deviate," (Qur'an 61:5).

So, Iblees gives us his plan. Have anyone of you heard of the repo-man? The repo-man is a person who comes and takes your car if you don't make your car payment. Subhan'Allah (glory be to God) when I was in college, I received credit card offers all the time, with very high credit limits. Now that I'm married with children and a job, alhamdullilah (praise be to Allah), I haven't gotten one credit card offer. Why is that? Because they want to catch you when you're young; because they know that most college students can't control their desires. College students tend to spend money that they can't pay the bill for when it comes. People will come to your house and take your iPod, your laptop, and the best of whatever they can find. So the job of the repo-man is to take the most valuable commodity you have. Shaytan works the same way.

Iblees is coming for us, and when he comes to us, he's coming to take the most valuable commodity we have. We might be worried that Iblees is coming to take our Lexus, or our PS3, or our concert ticket. But Shaytan is not interested in taking all that. He will come to take our Islam. How many of us feel that we're lucky to be Muslim? When we hear this, we should think, subhan'Allah, my treasure is my deen (faith). If you want to know how valuable Islam is, go to Surah Al 'Araf (Qur'an 7). Even when the people enter Paradise, they realize their greatest blessing is Islam and they say: 

"Praise to Allah, who has guided us to this; and we would never have been guided if Allah had not guided us," (Qur'an 7:43).

How many of us have felt this value for our deen, knowing that Iblees, the "repo-man", wants this most valuable of things from us? That's why when you're sitting in a philosophy class and you start having doubts remember that Iblees's primary target is your faith.

How do people treat the most valuable commodity that they have, like the Mona Lisa? How many of you have been to the Louvre before? If you visit museums, you see the "priceless antiquities" have lasers and other security devices. If you cross the wrong line, helicopters and police come after you. Do we protect our Islam the way these priceless commodities have been protected? Do we protect our Islam knowing that this enemy is constantly trying to take it from us? This is a very important point, because in the ayah (verse) Shaytan uses two forms of emphasis (laam at-tawkeed and nun at-tawkeed) to say, "Wallahi I will definitely take them off the straight path!"

What is the remedy for this in Surah Al Fatiha? 

That's why Allah made it an obligation to read Surah Al Fatiha at least seventeen times a day, because we have an enemy coming after us at all times, 24 hours a day, 7 days a week, 365 days a year. That's why we need this du`a'. Now when we say it, we should feel as if we need to say this to protect ourselves.

Then Shaytan continued. He said: 

"Then I will come to them from before them and from behind them and on their right and on their left, and You will not find most of them grateful [to You]." (Qur'an 7:17)

Now, maybe after hearing this, some of us will still think, "Hey, I've got Norton Anti-Virus, I'm good. Shaytan can't get me." As I said earlier, this is the person who Shaytan got. Abdullah ibn Masood radi Allahu `anhu (may Allah be pleased with him) related a hadith related by Imam Ahmed with a strong isnad (chain of narration). He said, "One day we were sitting with the Prophet and he drew a straight line. He said, "This is the way of Allah ." Then the Prophet drew lines perpendicular to this straight line and he said, "On every one of these lines is a Shaytan calling you to his path." So there's a Shaytan calling Muslims to get high, calling Muslims to hang out with the opposite gender, calling Muslims to commit acts of homosexuality. On every one of these ways there's a Shaytan telling you that communism or secularism or nationalism is better than Islam. These are the things that you will hear in your universities. Shaytan will work on you in every way that you can think of, especially in concepts (i.e. how you think about life). Suhban'Allah, the Prophet pointed at the first straight line that he drew and he read this verse from Surah Al An`am, 

"And this is My path, which is straight, so follow it; and do not follow [other] ways, for you will be separated from His way. This has He instructed you that you may become righteous." (Qur'an 6:153)

When we go to the Qur'an we notice something interesting. Whenever Allah uses the word "darkness", or words that symbolize misguidance, He uses those words in the plural form. But, whenever He uses words to symbolize guidance, like "light", He uses those words only in the singular form. For example, Allah says, 

"Allah is the protector of those who believe. He brings them out from darknesses into the light. And those who disbelieve - their allies are Taghut. They take them out of the light into the darknesses. Those are the companions of the Fire; they will abide eternally therein," (Qur'an 2:257)

Another example is in the sixth chapter of the Qur'an where Allah says, 

"And is one who was dead and We gave him life and made for him light by which to walk among the people like one who is steeped in darknesses, never to emerge there from? Thus it has been made pleasing to the disbelievers that which they were doing," (Qur'an 6:122)

This verse was sent when `Umar accepted Islam. Why does Allah use light in the singular and darkness in the plural? Because Allah wants to show us that guidance can only be obtained by traversing siratul mustaqeem (the straight path) and there's only one straight path: 

"Say, 'Indeed, the guidance of Allah is the [only] guidance; and we have been commanded to submit to the Lord of the worlds,'" (Qur'an 6:71)

However, the ways to be misguided are innumerable.

Source: SuhaibWebb - Lecture by Suhaib Webb, Transcribed by Fuseina Mohamad