During the Khilafah, or Caliphate of Umar Ibn Al-Khattab, the Muslims were rapidly expanding the borders of their domain because of the favor which Allah bestowed upon His loyal servants. This period was the greatest expansion of any nation in the world's history, not merely because of the rate of expansion, and the incredible odds faced by the Muslims from doing so, but also because the lasting impact of these military expansions spread the religion of Allah far and wide, and with such great strength that has never been matched before since Man's creation. The results of the tremendous successes experienced by the Muslims during this time, both on and off the battlefield are purely a result of the mercy of Allah, without which, none of this would have been possible.

The reason the Muslims were blessed with the mercy of Allah was not because they had the greater weapons with which to fight the enemy. If it were based on military capability, the Muslims would have been squashed by both the Persians and the Byzantine Romans, because the former two were the empirical superpower military forces of their time. The reason the Muslims won was by no means because of their wealth, for had it been based on such, the Muslims would not have made it out of the very desert in which they and their ancestors were known to be poor nomads who often starved to death. And certainly, the victory of the Muslims could not be attributed to any materialistic achievement or possession, for as stated, the only wealthy nations of the region were the Persians and the Byzantines. The only reason the Muslims were so successful was because they possessed faith in Allah that strongly emanated from them through their actions. They obeyed Allah and His Messenger (SAWS), and avoided that which displeased them. Because of their Taqwa, or their fear of Allah, they were bestowed with the success of this world, and the success of the Hereafter by the Lord of this world and the Lord of the Hereafter, Allah, our Creator, the One deserving of our full obedience, and the only One who has any and all right to be worshiped.

On the march towards a decisive battle with the Persians, Umar Ibn Al-Khattab (R) wrote to the general of the Muslim army in Iraq the following letter which we owe it to ourselves to take great  advantage of and implement its lessons into our lives so that we may also receive the world's, but more importantly the Hereafter's success from Allah:

The Letter

“I am ordering you and the troops who are with you to fear Allah in all circumstances, for fear of Allah is the best weapon against the enemy and the strongest stratagem in the war. I am commanding you and those who are with you to be more careful in avoiding sin than in avoiding your enemy, for the sins of the army are to be feared more than their enemy. The Muslims are supported by their enemy's disobedience to Allah; weer it not for that, we would not have any strength, for our numbers are not like theirs and our weapons are not like theirs. If we were equally matched in sin, they would have an advantage over us in strength, and if we did not have an advantage over them by our virtue, we would not be able to defeat them by our strength. Remember that you have over you protectors from Allah who know what you are doing, so feel shy before them and do do any act of disobedience towards Allah. You are (striving) for the sake of Allah; do not say that our enemy is worse than us and will never prevail over us even if we commit sin. A people may be defeated by others who are worse than them, just as the Children of Israel were defeated by the Kafir Magians when they did deeds that angered Allah, and,

{...They entered the very innermost parts of your homes. And it was a promise [completely] fulfilled.} (Qur'an 17:5)

Ask Allah for help against your evil whims and desires just as you ask him for help against your enemies. I ask Allah for that, for us and for you. Be kind to the Muslims on their march. Do not exhaust them on their march, lest they reach their enemy weakened from their journey, for they are marching towards an enemy that has not been traveling, and that has strong horses and riders. You and those who are with you should rest for one day and night every week, so that they will be able to regain their strength and lay down their weapons and belongings. Do not camp near the towns of people who have a treaty with us or are under our protection, and do not let any of your companions interact with them. Do not annoy any of the townspeople at all, for they are protected and you are being tested with regard to fulfillment of the treaty, just as they are being tested with regard to their patience in adhering to it. So long as they are keeping their promise to you, keep your promise to them. Do not seek victory against your enemies by oppressing those with whom you have a treaty. When you reach the closest point of enemy land, send out spied, for none of their affairs should be hidden from you. You should have with you Arabs and local people whom you trust and who you feel are sincere, for the news of a liar will be of no benefit to you, even if he tells the truth sometimes. The dishonest one is a spy against you, not for you. When you draw closer to the enemy's land you should send out scouts and raiding parties to cut their supply lines and try to find their weak points. Choose people of wisdom and strength among your companions for these missions, and choose the best horses. If they see the enemy the best way to deal with them is by means of good advice from these people. Put the people of Jihad, patience, and toughness in charge of these raiding parties, and do not show favor to anyone on the basis of whims and desires, because this may affect the whole affair and lead to bad consequences. Do not send any scouts or raiding parties in a direction in which you fear they may be exposed to danger. If you sight the enemy, then bring back your scouts and troops. But do not hasten to engage in fighting unless you are forced to, until you have the opportunity to find their fatal weak points and have studied the land until you know it as well as its people do. If any prisoner is brought to you with whom you do not have a treaty, you should execute him as to strike fear into your enemies and the enemies of Allah. Allah is the best disposer of affairs for you and those who are with you; He is the One Who grants victory to you over your enemy, and Allah is the One Whose help we seek."

Recorded in Al-Farooq Umar Ibn Al-Khattab, by Muhammad Rasheed Rida, pp 119, 12

The Lessons

From this epic letter we can learn numerous critical lessons which we absolutely need to apply to our everyday lives, whether or not we are anywhere near a battlefield. Many of the same principles apply, nonetheless.

• We need to fear Allah and remain dutiful to Him in all situations. Remaining obedient to Allah is a greater factor towards our success and is more important than any other strives we can make. If we make millions of dollars, and the whole world supports us, but we are disobedient to Allah, then it is all worth nothing, because our disobedience to our Creator outweighs all else. Similarly, if we are obedient to Allah and fear Him in our actions, then even if we have no wealth and the whole world is against us, then we are in the best of conditions because our Lord, and our Master, Allah (SWT) is pleased with us, so nothing else can outweigh that. This principle applies to us as individuals as well as the Ummah as a whole.
• Umar (R) pointed out that there are angels who watch over the Muslim army, so he commanded his soldiers to be shy from them and be ashamed of committing sins in front of them. Just as there are angels over Muslim armies, each human being always has two angels with him or her at all times recording every single one of our deeds, both the good and the bad. So just as Umar (R) commanded his soldiers to shy away from sinning in front of the angels present on the battlefield and in the course of Jihad, we also need to be shy from the angels who accompany us constantly, recording each and every deed we commit, leaving nothing.
• We should not expect that because our enemy sins more than us that it means we can take them as a standard to justify our own sins. This is what the Children of Israel did, and so Allah empowered their pagan enemies against them, and the Children of Israel, despite being the Muslims of their time, were defeated.
• The only source of victory is Allah. It is imperative that we seek the guidance of Allah as well as His will for our victory on the battlefield and in our lives.
• We as Muslims must abide by our commitments. Although the treaties Umar (R) discussed were in regards to peace treaties between the Muslims and other people, we also need to stay true to our word as Muslims in our everyday dealings amongst ourselves as well as with Kuffar. One of the signs of hypocrisy is that one makes promises and does not fulfill them.
• Umar (R) ordered the general of the Muslim army, Sa'id Ibn Abi Waqqas to be merciful to the Muslim soldiers. Umar told him to give the Muslims plenty of time to rest, and not to overwork them. It is important for those of us who are in power or leadership, as well as the rest of us as well to keep this principle high on our list, because it would be foolish for us to expect Allah to have mercy us if we pay no mind to showing mercy towards our fellow Muslims.

Though more applicable to military situations, there is still great wisdom to be found in recognizing these lessons as well:

• Umar (R) was sure to emphasize using scouts to gather information on the enemy. Not only that, but in case these scouts were to be captured by the enemy or were forced to fight them, they were to be chosen from beforehand from among the strongest of the army. This is to create a strong psychological impact on the enemy, impressing them with the best of the strength of the Muslim army, even though the rest of the army may not be as strong as those scouts.
• Gathering information on the enemy is not for the desire to fight them, but rather as a precaution in case fighting was inevitable. Muslims should not desire to fight if it is not necessary, but should it be necessary, then we must be ready for it. Preparing weapons, troops, as well as information on the enemy is critical, so that if fighting occurs, we would be capable of our defense by Allah's will.