Madarij as-Salikeen, 1/299
Ibn Qayyim (rahimahullah) said:
“Sin may be more beneficial for a person, if it leads him to repent, than doing a lot of acts of worship. This is what is meant by the words of one of the salaf:
‘A person may commit a sin and enter Paradise because of it, or he may do an act of worship and enter Hell because of it.’
They said: ‘How is that?’
He said: ‘He may commit a sin and continues to think about it, and when he stands or sits or walks he remembers his sin, so he feels ashamed and repents and seeks forgiveness and regrets it, so that will be the means of his salvation.
And he may do a good deed and continue to think about it, and when he stands or sits or walks he remembers it and it fills him with self-admiration and pride, so it is the cause of his doom.
So the sin may be the factor that leads him to do acts of worship and good deeds and to change his attitude so that he fears Allah and feels shy before Him and feels humiliated before Him, hanging his head in shame and weeping with regret, seeking he forgiveness of his Lord. Each of these effects is better for a person than an act of worship that makes him feel proud and show off and look down on people. Undoubtedly this sin is better before Allah and is more likely to bring salvation than one who admires himself and looks down on others, and who thinks that he is doing Allah a favour. Even if he says words that indicate something other than that, Allah is the Witness over what is in his heart. Such a person may feel hatred towards people if they do not hold him in high esteem and humiliate themselves before him. If he were to examine himself honestly, he would see that clearly.”
The last campaign Abu Ayyub Al-Ansari (may Allah be pleased with him) took part in was the one prepared by Mu’awiyah and led by his son Yazid against Constantinople. Abu Ayyub at that time was a very old man, almost eighty years old. But that did not prevent him from joining the army and crossing the seas as a graze in the path of God. After only a short time engaged in the battle, Abu Ayyub fell ill and had to withdraw from fighting. Yazid came to him and asked..
“What is it you need, Abu Ayyub?”
“Convey my salaams to the Muslim armies and say to them:
‘Abu Ayyub urges you to penetrate deeply into the territory of the enemy as far as you can go, that you should carry him with you and that you should bury him under your feet at the walls of Constantinople.”‘ Then he breathed his last.
The Muslim army fulfilled the desire of the companion of the Messenger of God. They pushed back the enemy’s forces in attack after attack until they reached the walls of Constantinople. There they buried him.
When Khalid bin Waleed (may Allah be pleased with him) reached Yarmook with his army to fight the Romans, he addressed them saying:
“Oh mujahideen! This is a memorable day. It is the day on which our faith will be tested and tried. Today we should avoid every kind of arrogance, pride and not contend for individual glory or egoistic bragging..
“Oh mujahideen of Islam! Fight only to gain the Goodwill of Allah Almighty. In the Muslim army today there are many great generals: each of them is worthy and can be entrusted with the permanent command of this army. Today you have assigned me this honor of commanding the Muslim army. So I hope that for the honor and victory of Islam, today we will enter the battlefield of Jihad as one. Allah will be our Supporter and Defender?”
Then both the armies confronted each other at Yarmook. The Roman general, Mahan, scornful addressed his counterpart, Khalid bin Waleed (may Allah be pleased with him) and said:
“It looks as if poverty, nakedness and starvation has compelled you to come here. If you wish I am willing to give each of you ten dinars, expensive clothing and good food. You can take these things and leave. Next year too I can send you these things; you do not have to take the trouble to come here?”
Khalid bin Waleed (may Allah be pleased with him) was enraged on hearing these scornful and arrogant words, and to break this arrogance, he answered:
“Mahan listen to me very carefully! You are mistaken about the reason why we are here. We are people who drink the blood of our opponents. We have heard that Roman blood is very delicious, and we have come here to enjoy it.”