The Messenger of Allah (sallallahu alahi wa-sallam) said, 'There is no one
among you but there has been appointed for him one qareen from among the jinn
and another from among the angels.' They said, 'For you too, O Messenger of
Allah?' He said, 'For me too, but Allah has helped me against him (the jinn
companion) and he has become Muslim, so he does not tell me to do anything but
good.' [Saheeh Muslim (4/2168, hadeeth no. 2814)]
Both, the angel qareen and the jinn qareen have an influence upon the person.
The former inspires good deeds and the latter persuades him to evil deeds. It is
narrated from Ibn Mas'ood that the Messenger of Allah (sallallahu alahi
wa-sallam) said, 'the devil has a hold over the son of Adam, and the angel has a
hold over him. The hold of the devil tempts man to do evil and deny the truth.
The hold of the angel encourages man to do good and believe in the truth.
Whoever experiences anything of this sort, let him know that it is from Allah,
and let him praise Allah. Whoever experiences anything of the other, let him
seek refuge with Allah from the accursed Shaytan.' [See, Tafseer Ibn Katheer,
Soorah al-Baqarah (2): 268]