These two sayings attributed to the Prophet, as well as other sayings and Quranic verses, have been understood by many Muslims, especially those who have accepted Islam in a Western environment, to teach that one must actually erase one's connections to their own prior culture and identity, and to adopt the culture and identity of others, to become immersed in an ultra-conservative "Islamic" culture.
Thus, it is not that unusual to see in Western cities men in traditional Indian or Arabic clothes, donning a Jalabiyyah or a Shalwar Kameez, believing this is a reflection of Islamic norm. It is also common for such enthusiastic converts, especially in the period early after their conversion, to be quite argumentative with other Muslims, urging them to follow suit in their choice of wardrobe. They often say that it is Sunnah, the Prophet's tradition, to somehow adopt this style.
Authentic Islamic culture?
To address this issue, one must understand that first and foremost, Islam is a religion, an ideology of Divine Origin whose main focus is spiritual. The Five pillars of Islam all revolve around theological constructs, and while it is indeed true that all Muslims share this in common, it does not seem prudent to call this a "culture". All societies and groups that have accepted Islam have many common features that have entered their cultures, but for a Muslim the only requirements are to obey God and his messenger (Muhammad) and to apply Islamic principles to life as much as possible.
The application of teachings not covered in the five pillars, what one may call secondary principles (Furu'), varies in style from place to place. Let us take an example of one such command from the Qur'an itself:
And say to the believing women, they should lower their gaze, guard their modesty, and place their head scarves [Khumuri-hinna] over their bosoms...[ 24:31]
This Quranic instruction has been applied in various ways in the Muslim world. While the intent and affect are the same, the style and method of application has varied, from the Tudung and Baju Melayu of the Malaysian Muslims, the various garments and scarves in the African countries, and so forth. All these have attempted to obey this Quranic directive, thus creating their own unique expressions.
Perhaps another good example is removing one's shoes upon entering a residence. This is done, religiously, upon entering a Mosque or when commencing prayers. These are the only times when it is necessary, but nonetheless removing shoes at the door of a house has entered the culture of many Muslims. We have pointed out these things to show that to accept Islam does not require abandoning one's culture, the only requirements are to Obey God and his messenger. Don't make the religion hard, as that is not the wish of God.
What about Muslim unity?
Strength exists in diversity. This is demonstrated in the last pillar of Islam, the Hajj. One will see in Makkah during the pilgrimage people of all colors, ethnicities, social and economic backgrounds, all gathered together for the worship of Allah. Another good example is the Salaah, performed in the same language, Quranic Arabic, in an universally recognized format. An Arab Muslim can go to a Mosque in Nigeria and find that the Salaah is performed in the same manner.
The spiritual practices of Islam create an environment in which brotherhood, tolerance, love and compassion can thrive and flourish. This does not require uniformity in thought, understanding and appearance.
And if God had so willed, he would have made you one 'Ummah', but [differences exist in order to] test you in what you have been given. So, compete with each other in goodness..[ Q 5:48] 3
Is Nationalism compatible with Islam?
The term 'Nationalism' means different things to different people. It can mean ethnic pride to one, racism and discrimination to another. There is nothing inherently wrong with national or ethnic pride, on the contrary, caring for and supporting worthwhile causes in one's community is noteworthy and commendable from an Islamic point of view.
This is especially important for Western Muslims to understand, as we are so quick to express solidarity with Muslims in other lands, suffering in 'Iraq, Palestine, Kashmir, etc.. and yet refuse to vote, on the grounds that it is of "no concern" to get involved in "Kafir politics". Too many of us who live in the West will engage in propagation work and not work to pay our bills and support our families.
Islam is a force of reality and spirituality. It should make us change for the better, not the worse. It is to be a source of enlightenment to the believer, and a source of mercy and assistance to any observer. It should not cause us to reject involvement in actions which are of benefit to our native societies, regardless of their religious label.
[God swears ] By the time, surely, humans are in consistent loss, except those who believe, do righteous works, and enjoin mutual [calling to] truth, and mutual [reminders of ] patience. [103:1-3]
Surely God does not change the condition of a people, until they change what is in themselves[13:11]
O believers! Save yourselves and your families from a fire whose fuel is men and stones [66:6]
On the other hand we have an equally distressing reality, and that is isolationism. Isolationism can be a vice, and not a virtue. Attitudes against Inter-racial marriages, or those that cross tribal or caste lines display ignorance of Islamic teachings, a lack of internalization of the words of Allah. Another example of isolationism is the idea prevalent among new Muslims that social interactions with the "disbelievers", even among Non-Muslim family members, are discouraged, creating unneeded tensions and bad feelings.
"O Mankind! Surely We have created you from a man and a woman; made you into nations and tribes, so that you will know each other. Surely, the most honorable of you in God's sight is the most dutiful [to God] among you"[ 49:13]
"And among his signs is the creation of the Heavens and the Earth, as well as the differences in your languages and colors. Truly, in these are signs for intelligent people"[ 30:22]
Islam is not a tribal or "group" religion. It is an invitation for all mankind. All of us are God's creation, and if we feel or treat someone different because of their tribal, religious, or racial label, we are actually treating that person as if they have been created by a different god. If we do that, then we are internalizing as well as externalizing Shirk, the worse sin. God wants us to love each other, to learn from each other. If we miss that lesson, then we have strayed far away from God, the Lord of the worlds.
In short, a balance must be found between ignoring one's own needs by advocating a cause far away, and the equally dangerous self-defeating isolationism, a feeling that one's own "Muslim group" is better than other Muslims on the other hand.
This balance is found not in reading inspiring words, but in true internalization of the words of Allah, of seeing all people as God's creation, worthy of respect and decent treatment, despite differences in opinion, theology, color, caste or ethnic origin.
 Mubarakpuri, Safi-ur-Rahman, Ar-Raheeq Al-Makhtum (Riyadh: Dar-us-Salam publications, 1996), pp. 466
 Sahih Bukhari 71:2026
 Obviously this verse refers to God's desire for diversity in his creation, not a single, monolithic picture. Also of interest is that this statement appears in a context of debate between the Muslims and the People of the Book.