To locate the Stormshore Tabernacle and Vicar Humbletoes, you need to gain access to Baldur's Gate's lower city. Once you're in the lower city, seek out the Stormshore Tabernacle, where Vicar Humbletoes serves as the merchant. You can purchase the Reviving Hands from him or attempt to steal them, but it's advisable not to resort to violence, as merchants' inventories vanish upon their death.