Commentary:
The subject of the previous verse was the battle of Uhud connected with which is the battle of Hamra' al-Asad which forms the subject of the present verse. Hamra' al-Asad is a place eight miles away from Madinah.
The background of this event, mentioned briefly under introductory remarks about verse 151, is that the disbelievers of Makkah left the battlefield of Uhud, reached a certain distance where they realized that they had made a mistake by retreating. Since they had almost won the battle, they should have gone for the final assault and finished off the Muslim forces. The thought so gripped them that they started getting ready to march back to Madinah. But, Allah Almighty cast such awe and fear in their hearts that they found it more convenient to march back home to Makkah. They still left a message with a passing group of travellers to Madinah asking them to give a warning to Muslims that they were coming back after them with all their awesome strength. The Holy Prophet ﷺ found this out through a revelation and he reached Hamra' al-Asad in hot pursuit (Ibn Jarir, cited by Ruh al-Ma'ani).
It appears in Tafsir al-Qurtubi that, on the second day of Uhud, the Holy Prophet ﷺ made an announcement before his mujahidin that they have to pursue the disbelievers but the attacking company will be composed of those who were active participants in yesterday's battle. Two hundred مجاھدین mujahidin rose following this announcement.
A report in Sahih al-Bukhari states that seventy people stood up following the announcement by the Holy Prophet ﷺ as to who was ready to go after the disbelievers. Among those were people who had been severely wounded in the battle a day earlier, some even had to be helped in walking. This blessed company marched to apprehend the disbelievers. When they reached Hamra' al-Asad, they met Nu'aym ibn Masud who told them that Abu Sufyan has assembled together a much larger force once again and he is all set to invade Madinah and eliminate its people. Injury-ridden and much weakened Companions ؓ heard this disturbing news yet it was in one voice that they said: We do not know him حَسْبُنَا اللَّـهُ وَنِعْمَ الْوَكِيلُ (Allah is sufficient for us and He is the best caretaker.)
On the one hand there was this news broken to Muslims so they get terrorized, but nothing of this sort happened to them. On the other hand, there was the instance of Ma'bad al-Khuza` i, a man from the tribe of Bahl Khuza` ah. He was on his way to Makkah. Though not a Muslim, he was a well-wisher of Muslims - his tribe was an ally of the Holy Prophet ﷺ . So, when he saw Abu Sufyan repenting his retreat from Madinah and all too resolved to go back and fight, he told Abu Sufyan: 'You are making a mistake by thinking that Muslim forces have become weak. I have just passed by a huge army of theirs camped at Hamra' al-Asad. Armed with an array of men and materials, they are about to set out in hot pursuit against you.' This report from him put the awe of Muslim forces in his (Abu Sufyan) heart.
This event has been related in three verses (172-174) given above. It has been said in the first verse (172) that despite injuries and hardships from the Battle of Uhud, when Allah and His Messenger called them up for another Jihad, they were ready for that too. Worth noticing at this point is the fact that the Muslims being praised here had two distinguishing features. The first one appears in مِن بَعْدِ مَا أَصَابَهُمُ الْقَرْحُ (even after they had received the wound) which means that those who responded to the call of Allah and His Messenger were people wounded at the Battle of Badr. Seventy of their brave companions had met their martyrdom on the battlefield while they themselves were riddled with injuries all over their bodies, yet when they were called to serve again, they immediately agreed to join the Jihad.
The second distinctive feature has been mentioned in the words: them who did good and feared Allah) which established that these people were not simply some great achievers on the battlefield striving incessantly and staking their lives for a noble cause, but they also imbibed in their person the highest virtues of Ihsan (righteous conduct) and Taqwa (fear of Allah). Thus, this very blessed combination of virtues is the cause of their great reward.
Removing a doubt
Let there be no doubt about the word: مِنْهُمْ (literally of them' ) used here. It should not be taken to mean that all these people were not armed with the virtues of Ihsan and Taqwa - only some of them were. The simple reason is that the preposition: مِن min (of, some of) used here is not divisive or partitive. It is, rather, doubtlessly narrative which is confirmed by the very opening words of this very verse: الَّذِينَ اسْتَجَابُوا (Those who responded to the call). From this, it is clear that such response and submission simply cannot materialize without having the qualities of Ihsan and Taqwa ingrained in one's personality. That is why most commentators have declared that the preposition: مِن min (of, some of) has been used here in the narrative sense. In short, the essential meaning of the verse is that all these people had rewards waiting for them.
Striving to achieve something good even at the cost of one's life is not enough unless there is total sincerity behind it
Anyway, this particular mode of address leads us to an essential rule of conduct which is: No matter how good is an effort made and no matter how many sacrifices of wealth and life one makes to achieve that end, it can be reward-worthy in the sight of Allah only when it is simultaneously backed by Ihsan and Taqwa. Therefore, the essence of the observation is that the deed undertaken must be for the good pleasure of Allah alone. Otherwise simple feats of bravery, some of which come even at the cost of one's dear life, are just about no lesser among disbelievers as well.
In its ultimate reality, the command of the Messenger of Allah is the command of Allah.
In this event, it will be recalled that the command to pursue the disbelievers was given by the Holy Prophet ﷺ . This does not find mention in any verse of the Holy Qur'an. But, in this particular verse, when the obedience of those people is praised, the command was attributed to both Allah and His Messenger as evident from the words of the text: الَّذِينَ اسْتَجَابُوا لِلَّـهِ وَالرَّسُولِ (172): 'Those who responded to the call of Allah and the Messenger. This proves very clearly that the command which the Holy Prophet ﷺ gives is also the command of Allah even though it has not been mentioned in the Book of Allah.
As for those irreligious deviants who reject Hadith and belittle the status of the Messenger of Allah by restricting it to that of a courier (God forbid), a simple statement, that Allah Almighty has openly declared the command of the Messenger as His own, should be enough to understand the truth - if understanding is what they seek. This statement, moreover, also makes it clear that the Messenger can also by himself and at his discretion, set up rules in accordance with expedient considerations, and all such rules have the same status as that enjoyed by the commandments of Allah.
The Definition of Ihsan
Mentioned several times during the comments given above, the word Ihsan generally means the performance of good deeds with the best of effort and discretion. However, the basic definition of Ihsan was given by the Holy Prophet ﷺ himself as reported in the well-known 'hadith of Jibra'il'. The actual words are:
اَن تَعبُد اللہ کاَنَّکَ تَرَاہُ فانِ لَّم تکُن تَرَاہُ فَاِنَّہُ یَرَاک
That is, worship Allah as if you are seeing Him; and if it is not possible for you to (imagine that you) see Him, then, (imagine that) He sees you anyway.
The Definition of Taqwa
The word, Taqwa, has been interpreted variously but the most comprehensive definition is what was given by the blessed Companion Ubayy ibn Ka'b ؓ when Sayyidna ` Umar ؓ asked him as to what Taqwa really was. Sayyidna Ubayy ibn Ka'b ؓ said: '0 Commander of the Faithful, you may have certainly passed by pathways full of thorns, have you not?' Sayyidna ` Umar ؓ said, 'Several times, of course.' Sayyidna Ubayy ibn Ka'b ؓ asked, 'What did you do at that time?' Sayyidna ` Umar ؓ said, 'I folded the hang of my dress and walked carefully.' Sayyidna Ubayy ibn Ka'b ؓ said, 'Enough. You said it. This is what Taqwa means. This mortal world of ours is a bed of thorns, full of the thorns of sins, therefore, one should live in this world in a way that one does not get entangled in the thorns of sin. The name of this attitude to life is Taqwa, the highest capital gain one can dream of.' The blessed Companion, Sayyidna Abu al-Darda' ؓ used to recite the following verse quite often:
یقولُ المَرُٔ فایٔدَتی ، و تقوَی اللہِ اَفضَلُ ما استَفَادا
"People say, ` my gain' and 'my money' while, really, the fear of Allah (Taqwa) is the best of what is gained."