The Pilgrim Separatists who settled at Plymouth Massachusetts and celebrated the first American Thanksgiving feast were Christians but the precedent for thanksgiving feasts traces back to the Old Testament and Judeo-Christian roots.
The tradition of thanksgiving feasts began with the Jewish people thousands of years ago. In the Old Testament God commanded the Jews to participate in a feast to celebrate the in-gathering of the harvest each year.
The purpose for celebrating the feast was two fold. First the feast day was meant to be a time of thanksgiving for all. And second the celebration was designed to impact the children of the nation with teachable moments where truths and knowledge of significant spiritual events of Jewish history could be passed on. The Word of God instructed the Jews about the importance of spending time with their children and teaching them to love God and His ways.
In Deut. 6:4-9 it says,“Hear, O Israel: The LORD our God, the LORD is one! “You shall love the LORD your God with all your heart, with all your soul, and with all your strength.”And these words which I command you today shall be in your heart. “You shall teach them diligently to your children, and shall talk of them when you sit in your house, when you walk by the way, when you lie down, and when you rise up.
The celebration of the Feast of In-gathering or Tabernacles was very participatory in nature. It was a week–long festival from the 15th to 21st of Tishri, which marked the completion of the whole harvest by the ingathering of the grapes. Because this was the time when everyone went out into the vineyards for their “communal working holiday” and lived in tents, it was an excellent time to remember the religious lessons of the forty years when the whole nation had lived in tents between their sojourn in Egypt and the possession of Canaan (Leviticus 23:34–36; 39–44; Deuteronomy 16:13–15). At the end of the agricultural year in the land to which God had brought them, thanksgiving was expected to be shown and appropriately celebrated (Exodus 23:16; 34:22).
By New Testament times the celebration of the feast of the In-gathering or Tabernacles was a spectacular ritual. Tents made of palm leaves were placed on rooftops, in courtyards, and in gardens, and people lived in them for the week. Two priestly processions left the Temple each morning; one went to collect leafy boughs, and the other went to the Pool of Siloam. When the priests returned there was a procession round the altar (once around for the first six days of the festival and seven times on the last day — a reminder of the ritual at Jericho, Joshua 6:3–4) and a tabernacle, or booth, was made for the altar itself. The water was poured out on the Temple steps so that it would flow down and out through the Temple to the world outside, and so indicate the way that the Jewish faith would satisfy the world. During the festival four large candelabra were set up in the Court of the Women, Everyone in Jerusalem could see the light, and there was music and dancing beneath with flaming torches. The light symbolized the revelation and truth of the Jewish faith.
The Feast of In-gathering or Tabernacles was meant and designed from beginning to end to be atime of supplying teachable moments, building memories, facilitating family unity and expressing community. The celebration involved participation by every member of the society. Males and females, the young and the old were expected to be active in the festivities. For centuries sociologists have marveled at the fact that the Jews could keep their national identity after losing their homeland. But it has been theorized that it was exactly the institution of such thick traditions as those involved in the celebration of thanksgiving that enabled the Jews to hold together throughout years without a land of their own.