SURAH AL-E-IMRAN: 121-122

TRANSLATION:

[3:121]
Recall the time when you left your house in the morning in order to place the believers in positions for fighting. {40} Allah is All-Hearing, All-Knowing.
[3:122]
When two of your groups were about to lose heart, {41} while Allah was their guardian! It is in Allah alone that the believers must place their trust.

INTERPRETATION:

{40} In Ghazvah Uhud (Ghazvat are those wars Muslims fought in which the Holy Prophet ﷺ himself took part) an army of three thousand non-believers from Meccah had attacked Medinah. The Holy Prophet ﷺ had taken Muslims to the plain next to the Uhud mountain to fight them. The next few verses make references to a number of incidents that took place during that battle. 

{41} When the Holy prophet ﷺ left Medinah to fight the non-believers he was accompanied by one thousand men. However, the leader of the Hypocrites, Abdullah Ibn Ubbi, deserted them with his three hundred men while on the way, saying that their recommendation was that they should fight the non-believers from within Medinah. As the Holy Prophet ﷺ had come out of Medinah against his recommendation he and his men would not join the battle. Upon seeing two other tribes of true Muslims, Banu Harthah and Banu Salmah, also became ambivalent and thought that seven hundred men were too few to fight three thousand men, therefore, they should also not join the battle. However, Allah Ta’alah helped them and they joined the battle. In this verse, there is a reference to these two tribes.

SURAH AL-E-IMRAN: 118-120

TRANSLATION:

[3:118]
O you who believe, do not take anyone as an insider but those from among your own selves. They would spare no effort to do you mischief. They want you to be in trouble. Malice has come out of their mouths while what is concealed in their hearts is still worse. We have made the signs clear to you, if only you understand.
[3:119]
Look, you are the ones who love them and they do not love you. You believe in all the books; (On the other hand,) when they meet you, they say, "We believe", and when they are alone, they bite their finger-tips out of rage against you. Say, "May you perish in your rage". Surely, Allah is All-Aware of what lies in the hearts.
[3:120]
If something good happens to you, it annoys them, and if something evil befalls you, they are delighted with it. If you keep patience and fear Allah, their cunning shall not harm you at all. Allah is All-Encompassing of what they do. 

INTERPRETATION:

{39} The tribes of Aws and Khazarj which lived in Medinah had had friendly terms with the People of the Book for ages. When people of these tribes converted to Islam they still maintained their friendly relations with the People of the Book. On other hand, while these People of the Book maintained superficial friendship with them, and some of them even pretended to have converted to Islam, but in their hearts they carried a lot of grudge against Muslims. Sometimes it happened that some Muslims, in their naivety, shared some secrets of their own community with these people. This verse of the Holy Quran warns Muslims not to trust them, and to absolutely avoid making them their confidants.

SURAH AL-E-IMRAN: 116-117

TRANSLATION:

[3:116]
Surely, those who disbelieve, neither their wealth nor their children shall help them against Allah; and they are the people of the Fire. They shall be there forever.
[3:117]
The example of what they spend in this worldly life is just like a wind that, having chill within, struck the tillage of those who wronged themselves, and destroyed it. {38} Allah has not wronged them; rather, they did wrong to themselves. 

INTERPRETATION:

{38} Allah Ta'alah repays the rewards of all the good deeds non-Muslims do within this world. They will not get any reward in the next world because of their non-belief. Therefore, their good deeds are like cultivated land, and their non-belief is like howling wind, which also has hail in it, and it destroys their well cultivated land.