It is He who sent down tranquillity into the hearts of the (48:4)

Almuntakhab Fi Tafsir Alquran Alkarim

It was He Who inspired peace and tranquility to the hearts of the believers whose breasts are filled with reverential awe, so that their hearts be impressed with the image of religious and spiritual virtues, and their deeds with wisdom and piety. And to Allah belong the forces, specific and generic of the heavens and the earth, and Allah has always been Alimun (Omniscient), and Hakimun (Wise)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(48:4) He it is Who bestowed inner peace on the hearts of the believers *6 so that they may grow yet more firm in their faith. *7 To Allah belong the legions of the heavens and the earth; Allah is All-Knowing, Most Wise. *8

It is He who sent down tranquillity into the hearts of the meaning

*6) "Sakinat" in Arabic is calmness and tranquillity and peace of mind. Here AIIah calls its being sent into the hearts of the believers an important factor in the victory that Islam and the Muslims achieved at Hudaibiyah. From a study of the conditions of the tuns one comes to know what kind of a Sakinat it was that was sent down into the hearts of the Muslims during that period and how it became a source of victory. If at the time when the Holy Prophet expressed his intention to go for 'Umrah to Makkah, the Muslims had become terror-stricken and started behaving like the hypocrites as if they were going into the very jaws of death, or if at the time when they heard the news on the way that the disbelieving Quraish were coming out in great strength to fight them, they had been alarmed as to how they would face the enemy un-armed, and thus become panic-stricken, obviously no benefits would have resulted from Hudaibiyah at all. Then, if at the time when at Hudaibiyah the disbelievers had stopped the Muslims from going any further, and when they had tried to provoke them by launching against them repeated sudden attacks, and when the rumor of Hadrat 'Uthman's martyrdom had spread, and when Abu Jandal had appeared on the scene as the very image of oppression and persecution, the Muslims had actually become provoked and broken the discipline that the Holy Prophet had instilled in them, the result would have been disastrous. Above all, if at the time when the Holy Prophet was going to conclude the treaty on the conditions which were un-acceptable to the entire party of the Muslims, the Muslims had happened to disobey him, the great victory of Hudaibiyah would have turned into a humiliating defeat. Thus, it was alI because of Allah's bounty that on all these critical moments the Muslims were blessed with full peace of mind with regard to the leadership and guidance of the Holy Prophet, the truth of Islam and the truthfulness of their mission. This is why they decided with a cool mind that they would face and accept whatever hardships they would encounter in the way of Allah; that is why they remained safe from fear, confusion, provocation and despair; that is why perfect discipline continues to prevail in the camp; and that is why, in spite of being deeply grieved at the conditions of peace, they submitted to the decision taken by the Holy Prophet. This was the sakinat that AIIah had sent down into the hearts of the Muslims, and it was aII because of this that the dangerous step of undertaking a journey for performing 'Umrah became the prelude to a unique victory.
*7) That is, "One Faith they already had before they set out on this expedition; they attained the additional Faith when they remained steadfast on the way of sincerity, piety and obedience in every trial that they faced in connection with the expedition. " This verse is one of those verses which show that Faith is not a static state which is incapable of growth, but it develops as well as decays and deteriorates. After embracing Islam till death the believer at every step in his life continues to be confronted with such tests and trials in which he has to take a decision whether in following the Divine Religion he is prepared to sacrifice his life, his wealth, his sentiments, desires, time, comforts and interests or not. If at the time of every such trial he adopts the way of sacrifice, his Faith progresses and develops, and if he turns away his Faith decays and deteriorates till a time may also come when the initial state of the Faith with which he had entered Islam is even endangered to be lost and destroyed. (For further explanation. see E.N. 2 of Surah AI-Anfal and E.N. 38 of AI-Ahzab).
*8) It means this: AIIah has such hosts by which He can destroy and exterminate the disbelievers completely whenever He wills, but He has deliberately and by wisdom only placed this responsibility on the believers that they should enter a conflict with the disbelievers and struggle to make the Religion of AIIah prevail and prosper in the world. In this way alone does a door to the enhancement of their ranks and successes in the Hereafter open as is being indicated in the following verse'.
 

It is He who sent down tranquillity into the hearts of the meaning in Urdu

وہی ہے جس نے مومنوں کے دلوں میں سکینت نازل فرمائی تاکہ اپنے ایمان کے ساتھ وہ ایک ایمان اور بڑھا لیں زمین اور آسمانوں کے سب لشکر اللہ کے قبضہ قدرت میں ہیں اور وہ علیم و حکیم ہے