Anas (RA) reported: Messenger of Allah (SAWS) said, “He who desires ample provisions and his life be prolonged, should maintain good ties with his blood relations.” [Sahih Bukhari and Sahih Muslim]
One who is benevolent and compassionate towards one’s own relatives stands to gain at least two definite advantages in this world besides the reward in the next. These two advantages are the increase in his subsistence and longevity of life.
Increase in subsistence means that Almighty Allah will increase the quantity of his worldly goods or his means of subsistence will be blessed by Him. Similar is the case of longevity of life. The life of such person is either actually increased (in terms of years) or his life is graced with the Blessings of Allah. Both interpretations are correct.
In a related Hadith, ‘Abdullah ibn ‘Amr reported: “The Prophet, (PBUH), said, ‘A person who maintains ties of kinship is not someone who only does so with those who maintain ties with him. A person who maintains ties of kinship is someone who restores them when they have been cut off.’” [al-Bukhari]
[Riyad as-Saliheen Chapter 40, Hadith 319]