Guardian angels

Guardian angels 

There are angels who take turns guarding each human , some by night and some by day. These angels protect each person from harm and accidents. There are also angels who take turns recording the good and evil deeds, some angels do this by day and some by night. 
There are two angels, one to the right and one to the left of each person, recording the deeds. The angel to the right records the good deeds, while the angel to the left records the evil deeds. 
There are also two angels that guard and protect each person, one from the back and one from in front. Therefore, there are four angels that surround each person by day and they are replaced by four others at night, two scribes and two guards. 

In the light of Ra'd (The Thunder):11

Hadith #1

 Holy Prophet (PBUH) said
“Angels take turns around you, some at night and some by day, and all of them assemble together at the time of the Fajr and `Asr prayers. Then those who have stayed with you throughout the night, ascend to Allah Who asks them, and He knows the answer better than they about you, "How have you left My servants'' They reply, "As we have found them praying, we have left them praying.''.

Hadith #2

  Holy Prophet (PBUH) said 
“Verily, every one among you has his companion from the Jinn and his companion from the angels.''
They said, "And you too, O Allah's Messenger'' He said,
“And I too, except that Allah has helped me against him, so he only orders me to do good.”

Muslim

Source : Tafseer Ibn-e-Kathir

Hadith #3

  The Holy Prophet (PBUH) said
Allah the Exalted said to guardian angels `If my slave intends to perform a good deed, then record it for him as one good deed; if he performs it, then record it for him multiplied ten folds. If he intends to commit an evil act but did not commit it, then record it for him as one good deed, if he left it for My sake. But if he commits it, then write it as one evil deed.