The deities in Toril take an active interest in their world, channeling power through their clerics, druids, rangers, paladins, and other worshippers and sometimes intervening directly in the affairs of mortals. At the same time, they plot, war, intrigue, and ally among themselves, between themselves and powerful mortals and with extraplanar beings such as elemental rulers and demons. In this they resemble their mortal worshipers, for to an extent deities are defined and shaped by their worshipers, their areas of interest, and their nature - for many deities are actually mortals who have gained the divine spark. Because they lose strength if their worship dwindles away and is forgotten, deities task spreading their praise and doctinre, recruiting new worshipers, and keeping the faith alive. In exchange for this work and to facilitate it, deities grant divine spells.
Worship
A weaponsmith might take Gond as his patron deity. but also pray to Tempus, Lord of Battles, before attemping to forge a fine sword. During a difficult forging or when striving to make a blade lucky for wielders, the same smith prays to Tymora. A weapon forged for guardians would involve prayers and offerings to Helm. A weapon to be wielded for justice (an executioner's blade, perhaps) would be dedicated to Tyr. Most people of Toril worship more than one deity on a daily basis, even if they dedicate heir lives to one patron deity. Some folk of Faerûn believe deities are akin to awesomely powerful mortals and are therefore prone to foubles, tempers, and the haste, mistakes, and emotions of mortals. Others see them as beyond mortal flaws or mortal comprehension. Overlaid on these extremes are beliefs as to wether deities like to intervene in mortal affairs daily, at crucial junctures, on whims, or to further mysterious or stated aims - or wether they remain aloof, influencing mortals only in suble, hidden ways or through dream visions or cryptic auguries. With this widely varying views come to a correspondingly wide range in practices of worship.
Patron Deities
The deities of Faerûn are deeply enmeshed in the functioning of the world's magical ecology and the lives of mortals. Characters of Toril nearly always have a patron deity. Everyone in Faerûn knows that those who die without having a patron deity to send a servant to collect them from the Fugue Plane at their death spend eternity writhing in the Wall of the Faithless or disappear into the hells of the devils or the infernos of demons.