What is the meaning of the Hadith: "The best charity is that given to a resentful relative," and what is its authenticity?

Imam Ahmad and Al-Darimi narrated the hadith: "Which charity is best? He said: That given to a relative who harbors enmity." This means that the best charity is that given to a relative who secretly harbors hostility, and in that is the maintaining of kinship ties and a defiance of Satan.