He's one of very few American Christians who follow what used to be the norm in many Protestant denominations — rejecting the celebration of Christmas on religious grounds.
"People don't think of it this way, but it's really a secular holiday," said Foster, a Princeton-based pastor in the United Church of God. He last celebrated Christmas when he was 8.
His church's objection to Christmas is rare among U.S. Christians. Gallup polls from 1994 to 2005 consistently show that more than 90 percent of adults say they celebrate Christmas, including 84 percent of non-Christians.
That's a huge change from an earlier era, when many Protestants ignored or actively opposed the holiday. But as it gradually became popular as a family celebration, churches followed their members in making peace with Christmas.
No quick change
The change didn't happen overnight. Through much of the 19th century, schools and businesses remained open, Congress met in session and some churches closed their doors, lest errant worshippers try to furtively commemorate the day.
"The whole culture didn't stop for Christmas," said Bruce Forbes, a religious studies professor at Morningside College in Sioux City, Iowa.
"Government went on as usual, business went on as usual, school went on as usual."
In researching his book, "Christmas: A Candid History," Forbes discovered that major American denominations — Presbyterians, Baptists, Quakers, Methodists and Congregationalists — either ignored the holiday or actively discouraged it until the late 19th century.
Lack of biblical sanction
That rejection was rooted in the lack of biblical sanction for Dec. 25 as the date of Jesus' birth, as well as suspicion toward traditions that developed after the earliest days of Christianity. In colonial New England, this disapproval extended to actually making the holiday illegal, with celebration punishable by a fine.
"Some somehow observe the day," wrote Boston Puritan Samuel Sewall on Christmas Day 1685, "but are vexed, I believe, that the body of people profane it, and blessed be God no authority yet compels them to keep it."
Displays Christmas tree
Some 322 years later, Sewall might be surprised to see his congregation — today known as Old South Church — proudly displaying a decorated Christmas tree outside the church.
"We think it's cheerful and seasonal," said Nancy Taylor, senior minister of Old South, one of America's most venerable congregations, counting among its past worshippers not only Sewall but Benjamin Franklin and Samuel Adams.
Now part of the United Church of Christ, Old South not only has a Christmas tree, but encourages its 650 or so members to exchange Christmas presents — although the focus is on charitable donations and service, rather than shopping.
"We are the descendants of the Puritans and Pilgrims, but we have loosened up a lot since then," Taylor said. "We have changed and adapted, and I think that's part of why we haven't died out."
Like Sewall's successors, the mainline Protestant churches have learned to accommodate Christmas. But the change came from the pews rather than the pulpit.
Christmas benefited from a 19th century "domestication of religion," said University of Texas history professor Penne Restad, in which faith and family were intertwined in a complementary set of values and beliefs.
Family-centered holiday
Christmas became acceptable as a family-centered holiday, Restad said, once it lost its overtly religious significance.
At the same time, aspects of the holiday like decorated trees and gift-giving became status symbols for an aspirant middle class. When Christmas began its march toward dominance among holidays, it was because of a change in the culture, not theology.
"In America, the saying is that the minister follows the people, the people don't follow the minister," Restad said. "This was more of a sociological change than a religious one. The home and the marketplace had more sway than the church."
That's partly why Christians like the United Church of God reject the holiday: They say divine instruction, rather than culture and society, should determine whether the holiday is appropriate.
"It's common knowledge that Christmas and its customs have nothing to do with the Bible," said Clyde Kilough, president of the United Church of God, which has branches all over the world. "The theological question is quite simple: Is it acceptable to God for humans to choose to worship him by adopting paganism's most popular celebrations and calling them Christian?"
There is still lingering unease with the holiday in denominations that once rejected it. This can be glimpsed in worries about commercialization and in individual Christians like Phillip Ross.
Ross is an elder at Covenant Presbyterian Church in Vienna, near Parkersburg. Well-versed in the history of Christianity, Christmas and Presbyterianism, Ross knows his church historically objected to Christmas.
On the other hand, Ross is also a father of two, and while he made up his mind to reject Christmas as a teenager, his children's early years included gifts, decorations and a tree.
"I have a love-hate relationship with Christmas," he said. "It seems obvious to me that there's nothing scriptural about it, but that's a hard sell with children."