There is a verse in Qura'n that encourages people of different races and cultures to get to know each other and get acquainted.
Also, there are several Hadeeths that encourage people to marry from different tribes and nations.

Sahih International: O mankind, indeed We have created you from male and female and made you peoples and tribes that you may know one another. Indeed, the most noble of you in the sight of Allah is the most righteous of you. Indeed, Allah is Knowing and Acquainted.

Pickthall: O mankind! Lo! We have created you male and female, and have made you nations and tribes that ye may know one another. Lo! the noblest of you, in the sight of Allah, is the best in conduct. Lo! Allah is Knower, Aware.

Yusuf Ali: O mankind! We created you from a single (pair) of a male and a female, and made you into nations and tribes, that ye may know each other (not that ye may despise (each other). Verily the most honoured of you in the sight of Allah is (he who is) the most righteous of you. And Allah has full knowledge and is well acquainted (with all things).

Shakir: O you men! surely We have created you of a male and a female, and made you tribes and families that you may know each other; surely the most honorable of you with Allah is the one among you most careful (of his duty); surely Allah is Knowing, Aware.

Muhammad Sarwar: People, We have created you all male and female and have made you nations and tribes so that you would recognize each other. The most honorable among you in the sight of God is the most pious of you. God is All-knowing and All-aware.

Mohsin Khan: O mankind! We have created you from a male and a female, and made you into nations and tribes, that you may know one another. Verily, the most honourable of you with Allah is that (believer) who has At-Taqwa [i.e. one of the Muttaqun (pious - see V.2:2). Verily, Allah is All-Knowing, All-Aware.

Arberry: O mankind, We have created you male and female, and appointed you races and tribes, that you may know one another. Surely the noblest among you in the sight of God is the most godfearing of you. God is All-knowing, All-aware.