They are also sinful in the view of wisdom, for it is obvious that enmity and love are opposites, just like light and darkness; while maintaining their respective essences, they cannot be combined.
If love is truly found in a heart, by virtue of the predomination of the causes that produce it, then enmity in that heart can only be metaphorical, and takes on the form of compassion. The believer loves and should love his brother, and is pained by any evil he sees in him. He attempts to reform him not with harshness but gently. It is for this reason that the Hadith of the Prophet (UWBP) says, “No believer should beangered with another and cease speaking to him for more than three days.”
If the causes that produce enmity predominate, and true enmity takes up its seat in a heart, then the love in that heart will become metaphorical, and take on the form of artifice and flattery.
O unjust man! See now what a great sin is rancour and enmity toward a brother believer! If you were to say that ordinary small stones are more valuable than the Ka‘ba and greater than Mount Uhud, it would be an ugly absurdity. So too, belief which has the value of the Ka‘ba, and Islam which has the splendour of Mount Uhud, as well as other Islamic attributes, demand love and concord; but if you prefer to belief and Islam certain shortcomings which arouse hostility, but in reality are like the small stones you too will be engaging in great injustice, foolishness, and sin!
The unity of belief necessitates also the unity of hearts, and the oneness of our creed demands the oneness of our society. You cannot deny that if you find yourself in the same regiment as someone, you will form a friendly attachment to him; a brotherly relation will come into being as a result of your both being submitted to the orders of a single commander. You will similarly experience a fraternal relation through living in the same town with someone. Now there are ties of unity, bonds of union, and relations of fraternity as numeous as the divine names that are shown and demonstrated to you by the light and consciousness of belief.
Your Creator, Owner, Object of Worship, and Provider is one and the same for both of you; thousands of things are and the same for you. Your Prophet (UWBP), your religion, your qibla are one and the same; hundreds of things are one and the same for you. Then too your village is one, your state is one, your country is one; tens of things are one and the same for you. All of these things held in common dictate oneness and unity, union and concord, love and brotherhood, and indeed the cosmos and the planets are similarly interlinked by unseen chains. If, despite all this, you prefer things worthless and transient as a spider’s web that give rise to dispute and discord, to rancour and enmity, and engage in true enmity towards a believer, then you will understand – unless your heart is dead and your intelligence extinguished – how great is your disrespect for that bond of unity, your slight to that relation of love, your transgression against that tie of brotherhood!
 Bukhari, Adab, 57, 62; Isti’dhan, 9; Muslim, Birr, 23, 25, 26; Abu Da’ud, Adab, 47; Tirmidhi, Birr, 21, 24; Ibn Maja, Muqaddima, 7; Musnad, i, 176, 183; iii, 110, 165, 199, 209, 225; iv, 20, 327, 328; v, 416, 421, 422.