The Quran

۞ وَاعبُدُوا اللَّهَ وَلا تُشرِكوا بِهِ شَيئًا ۖ وَبِالوالِدَينِ إِحسانًا وَبِذِي القُربىٰ وَاليَتامىٰ وَالمَساكينِ وَالجارِ ذِي القُربىٰ وَالجارِ الجُنُبِ وَالصّاحِبِ بِالجَنبِ وَابنِ السَّبيلِ وَما مَلَكَت أَيمانُكُم ۗ إِنَّ اللَّهَ لا يُحِبُّ مَن كانَ مُختالًا فَخورًا

Muhammad Asad

AND WORSHIP God [alone], and do not ascribe divinity, in any way, to aught beside Him.¹ And do good unto your parents, and near of kin, and unto orphans, and the needy, and the neighbour from among your own people, and the neighbour who is a stranger,² and the friend by your side, and the wayfarer, and those whom you rightfully possess.³ Verily, God does not love any of those who, full of self-conceit, act in a boastful manner;

The expression shay'an (here rendered as "in any way") makes it clear that shirk ("the ascribing of divinity to anything beside God") is not confined to a worship of other "deities", but implies also the attribution of divine or quasi-divine powers to persons or objects not regarded as deities: in other words, it embraces also saint-worship, etc.
I.e., "whether he belongs to your own or to another community". That the expression "your own people" (dhu l-qurba) refers to the community and not to one's actual relatives is obvious from the fact that "the near of kin" have already been mentioned earlier in this sentence. The Prophet often stressed a believer's moral obligation towards his neighbours, whatever their faith; and his attitude has been summed up in his words, "Whoever believes in God and the Last Day, let him do good unto his neighbour" (Bukhari, Muslim, and other compilations).
According to 'Ali ibn Abi Talib, 'Abd Allah ibn Mas'ud and other Companions, "the friend by your side" (as-sahib bi'l-janb) is one's wife or husband (Tabari). By "those whom you rightfully possess" (lit., "whom your right hands possess") are meant, in this context, slaves of either sex. Since this verse enjoins the "doing of good" towards all people with whom one is in contact, and since the best that can be done to a slave is to free him, the above passage calls, elliptically, for the freeing of slaves (Manar V, 94). See also surah 2, verse 177, as well as 9:60, where the freeing of human beings from bondage is explicitly mentioned as one of the objectives to which zakah funds are to be dedicated.