كتاب الزكاة
12  
The Book of Zakat
(12)
Chapter: The virtue of spending on one's family and slaves, and the sin of the one who neglects them or withholds maintenance from them
(12)
باب فَضْلِ النَّفَقَةِ عَلَى الْعِيَالِ وَالْمَمْلُوكِ وَإِثْمِ مَنْ ضَيَّعَهُمْ أَوْ حَبَسَ نَفَقَتَهُمْ عَنْهُمْ
Sahih Muslim 994

Thauban reported Allah's Messenger (ﷺ) as saying:

The most excellent dinar is one that a person spends on his family, and the dinar which he spends on his animal in Allah's path, and the dinar he spends on his companions in Allah's path. Abu Qilaba (one of the narrators) said: He (the narrator) started with family, and then Abu Qilaba said: Who is the person with greater reward than a person who spends on young members of his family (and thus) preserves (saves them from want) (and by virtue of which) Allah brings profit for them and makes them rich.
حَدَّثَنَا أَبُو الرَّبِيعِ الزَّهْرَانِيُّ، وَقُتَيْبَةُ بْنُ سَعِيدٍ، كِلاَهُمَا عَنْ حَمَّادِ بْنِ زَيْدٍ، - قَالَ أَبُو الرَّبِيعِ حَدَّثَنَا حَمَّادٌ، - حَدَّثَنَا أَيُّوبُ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَبِي أَسْمَاءَ، عَنْ ثَوْبَانَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ أَفْضَلُ دِينَارٍ يُنْفِقُهُ الرَّجُلُ دِينَارٌ يُنْفِقُهُ عَلَى عِيَالِهِ وَدِينَارٌ يُنْفِقُهُ الرَّجُلُ عَلَى دَابَّتِهِ فِي سَبِيلِ اللَّهِ وَدِينَارٌ يُنْفِقُهُ عَلَى أَصْحَابِهِ فِي سَبِيلِ اللَّهِ ‏"‏ ‏.‏ قَالَ أَبُو قِلاَبَةَ وَبَدَأَ بِالْعِيَالِ ثُمَّ قَالَ أَبُو قِلاَبَةَ وَأَىُّ رَجُلٍ أَعْظَمُ أَجْرًا مِنْ رَجُلٍ يُنْفِقُ عَلَى عِيَالٍ صِغَارٍ يُعِفُّهُمْ أَوْ يَنْفَعُهُمُ اللَّهُ بِهِ وَيُغْنِيهِمْ ‏.‏
Reference : Sahih Muslim 994
In-book reference : Book 12, Hadith 47
USC-MSA web (English) reference : Book 5, Hadith 2180
  (deprecated numbering scheme)