Is it permissible to donate five riyals daily to attain the angels' supplication: "O Allah, grant a successor to him who spends [in charity]"?

Charity (sadaqah) is among the best deeds and greatest acts of devotion. Allah has encouraged it and promised recompense to those who spend in charity, as He says: (And whatever you spend of anything, He will compensate it; and He is the best of providers). The Prophet, peace and blessings be upon him, said: "Every day two angels descend, and one of them says: 'O Allah, grant recompense to the one who spends [in charity],' and the other says: 'O Allah, bring destruction upon the one who withholds [charity].'" This is a promise of recompense for whoever spends seeking Allah's pleasure. The best charity is that given when one has sufficient means, as the Prophet, peace and blessings be upon him, said: "The best charity is that given when one has sufficient means, and begin with those whom you support."