Giving thanks to God before carving the turkey at Thanksgiving dinner. (1942)Thanksgiving was originally a religious observance for all the members of the community to give thanks to God for a common purpose. Historic reasons for community thanksgivings are: the 1541 thanksgiving mass after the expedition of Francisco Vásquez de Coronado safely crossing the high plains of Texas and finding game, and the 1777 thanksgiving after the victory in the Revolutionary War Battle of Saratoga. In his 1789 Proclamation, President Washington gave many noble reasons for a national Thanksgiving, including "for the civil and religious liberty", for "useful knowledge", and for God’s "kind care" and "His Providence". The only presidents to inject a specifically Christian focus to their proclamation have been Grover Cleveland in 1896, and William McKinley in 1900.Several other presidents have cited the Judeo-Christian tradition. Gerald Ford's 1975 declaration made no clear reference to any divinity.

The tradition of giving thanks to God is continued today in various forms. Various religious and spiritual organizations offer services and events on Thanksgiving themes the weekend before, the day of, or the weekend after Thanksgiving.

At home, it is a holiday tradition in many families to begin the Thanksgiving dinner by saying grace (a prayer before or after a meal).The custom is portrayed in the photograph "Family Holding Hands and Praying Before a Thanksgiving Meal". Traditionally, grace was led by the hostess or host, though in later times it is usual for others to contribute.