بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِِ 

In the Name of Allah, The All-Merciful, the Mercy-giving.

All Praise is to Allaah. 

Imaam al-Bukhaari (may Allaah have mercy on him) reported in his Saheeh  that ‘Aa’ishah (may Allaah be pleased with her) said: “I heard the Prophet (peace and blessings of Allaah be upon him) saying : ‘Souls are like conscripted soldiers; those whom they recognize, they get along with, and those whom they do not recognize, they will not get along with.’“  (Saheeh al-Bukhaari, Kitaab Ahaadeeth al-Anbiyaa’, Baab al-Arwaah junood mujannadah)

Abu Huraira reported Allaah’s Messenger (sallAllaahu ‘alayhi wa sallam) Saying: Souls are troops collected together and those who familiarised with each other (in the heaven from where these come) would have affinity, with one another (in the world) and those amongst them who opposed each other (in the Heaven) would also be divergent (in the world).  (Saheeh Muslim: The Book of Righteousness, Manners, and Joining Ties of Kinship)

Abu Huraira narrated directly from Allaah’s Messenger (sallAllahu ‘alayhi wa sallam) that he said: People are like mines of gold and silver; those who were excellent in Jahiliya (during the days of ignorance) are excellent In Islam, when they have an understanding, and the souls are troops collected together and those who had mutual familiarity amongst themselves in the store of prenatal existence would have affinity amongst them, (in this world also) and those who opposed one of them, would be at variance with one another.  (Saheeh Muslim: The Book of Righteousness, Manners, and Joining Ties of Kinship). Explanation of the first hadith:

 Ibn Hajar (may Allaah have mercy on him) said in his commentary on the hadeeth: “Concerning the phrase ‘Souls are like conscripted soldiers…’ al-Khattaabi said: ‘This may refer to their similarity as regards good or evil, righteousness or corruption. Good people are inclined towards other good people, and evil people are similarly inclined towards other evil people. Souls feel affinity with others according to the nature in which they were created, good or evil. If souls’ natures are similar, they will get along, otherwise they will not be on good terms with one another. It could be that what is being referred to is the beginning of creation in the realm of the unseen when, it is reported, souls were created before bodies, and used to meet one another and express their pessimism about the future. When souls have entered bodies (come to the physical realm) they may recognize one another from the past, and may be on friendly terms or otherwise based on that past experience.”

The hadeeth was also narrated by Muslim in his Saheeh, 4773. Al-Nawawi said: “With regard to the words of the Prophet (peace and blessings of Allaah be upon him), ‘Souls are like conscripted soldiers; those whom they recognize, they get along with, and those whom they do not recognize, they will not get along with’, the scholars said that the meaning is groups gathered together, or different types. As for them getting along, this happens because of something in common between them that Allaah has created. It was said that they are similar attributes that Allaah has created in them, or that they were created in a group and then dispersed in their bodies, so people who have similar characteristics will like one another, and those who do not have similar characteristics will not like one another. Al-Khattaabi and others said: this getting along with one another has to do with what Allaah decreed from the outset about the ultimate destiny of souls, whether they will be among the blessed [in Paradise] or the doomed [in Hell]. Souls are of two opposing kinds, and when they meet in this physical world, they will either love or hate one another depending on the way they were created. Good souls will be inclined towards other good souls, and evil souls will be inclined towards other evil souls. And Allaah knows best.

Source: Islam Q&A, Answer by Sheikh Muhammed Salih Al-Munajjid

Accessible: http://www.islam-qa.com/index.php?ref=3864&ln=eng