Sahih al-Bukhari Book 78, Hadith 15
That he heard the Prophet (ﷺ) saying, "The person who severs the bond of kinship will not enter
Paradise."
A man said, "O Allah's Messenger (ﷺ)! Inform me of a deed which will make me enter Paradise." The people said, "What is the matter with him? What is the matter with him?" Allah's Messenger (ﷺ) said, "He has something to ask (what he needs greatly)." The Prophet (ﷺ) said (to him), (In order to enter Paradise) you should worship Allah and join none in worship with Him: You should offer prayers perfectly, give obligatory charity (Zakat), and keep good relations with your Kith and kin." He then said, "Leave it!" (The sub-narrator said, "It seems that the Prophet (ﷺ) was riding his she camel."
I heard Allah's Messenger (ﷺ) saying, "Who ever is pleased that he be granted more wealth and that his lease of life be pro longed, then he should keep good relations with his Kith and kin."