"So give the relative his right," it is voluntary, and it is what Allah has commanded regarding upholding ties of kinship. As for His saying: "and the needy and the traveler," it refers to Zakat (obligatory alms).
Yahya said: They narrated to us that Zakat was ordained in Mecca, but it was not something with specified amounts.
﴿فَآت ذَا الْقُرْبَى حَقه﴾ فَهْوَ تَطَوُّعٌ، وَهُوَ مَا أَمَرَ اللَّهُ بِهِ مِنْ صِلَةِ الْقَرَابَةِ، وَأَمَا قَوْلُهُ: ﴿وَالْمِسْكِينَ وَابْنَ السَّبِيلِ﴾ فَيَعْنِي: الزَّكَاةَ.
قَالَ يَحْيَى: حَدَّثُونَا أَنَّ الزَّكَاةَ فُرِضَتْ بِمَكَّةَ، وَلَكِنْ لم تكن شَيْئا مَعْلُوما.
سُورَة الرّوم من (آيَة ٣٩ آيَة ٤٠).