Just as disputes and quarrels weaken Muslims spiritually, unity and solidarity strengthen them. For instance, destroying irreligious ideologies will be possible only when the Muslims unite.

However, what truly makes the believers' union so strong is their faith and loyalty. Since only genuine faith can engender true friendship and alliance, Muslims must love one another with a pure heart and for the good pleasure of Allah, without the slightest selfish interest. A union built on the strongest foundation known to humanity—the fear and love of Allah—will never shatter, unless Allah wills otherwise. With the following verse, Allah points out that success does not depend upon a group's size:

How many a small force has triumphed over a much greater one by Allah's permission! Allah is with the steadfast. (Surat al-Baqara, 249)

An Islamic union based on faith and devotion will provide Muslims with the necessary enthusiasm and willpower for great success.

In another verse, Allah reveals that although the deniers appear to be united, they have not achieved true unity:

Their hostility toward each other is intense. They are full of bravado in each other's company. You consider them united, but their hearts are scattered wide. That is because they are people who do not use their intellect. (Surat al-Hashr, 14)

Irrespective of how solid a union appears to be, it is in fact very unstable if it is not built on sincerity and genuine intentions, for this means that it is based only on various interests. And, when any of these interests is threatened, the union will fall apart quickly. Since Allah has revealed this secret in the Qur'an, the Muslims' union is not shaken by worldly losses; rather, it is strengthened. This awareness makes the union very solid. The great Islamic scholar Said Nursi uses the following example to explain why a union formed by sincere Muslims will be strong:

So we are surely in need of solidarity and true union, obtained through gaining sincerity—for the mystery of sincerity secures through four individuals the moral strength of one thousand one hundred and eleven—indeed, we are compelled to obtain it.

…If four times four remain apart, they have a value of sixteen. But if, through the mystery of brotherhood and having a common goal and joint duty, they unite, coming together shoulder to shoulder on a line, they have the strength and value of four thousand four hundred and forty-four. Just as numerous historical events testify that the moral strength and value of sixteen self-sacrificing brothers have been greater than that of four thousand.

The underlying reason for this mystery is this: Each member of a true and sincere union may see also with the eyes of the other brothers and hear with their ears. As if each person of a true union of ten has the value and strength of seeing with twenty eyes, thinking with ten minds, hearing with twenty ears, and working with twenty hands. (Bediuzzaman Said Nursi, Risale-i Nur Collection, “The Twenty-First Flash, Your Second Rule.”)