Religion was an integral part of the lives of the Arlington House inhabitants. All family members were devoutly Episcopalian and were faithful members of the congregation at Christ Church in Alexandria, Virginia. Mrs. Custis, the matriarch of the family, made sure that religion was central to the lives (at least externally) of every person that lived on the plantation, including the family's slaves. Personal papers, such as letters and journals of various family members document the importance placed upon religion by members of the Custis and Lee families. For this prominent Virginia family, religion influenced all aspects of life.
Mrs. Custis' Christian practice was a high priority in her life and this certainly impacted her interactions with those around her. The family routinely began each day with breakfast followed by morning prayers and then Bible reading (perhaps from the great Lee family Bible that waits in the Family Parlor even today). Often they would end their day the same way. Mrs. Custis— and later her daughter, Mrs. Lee— would often hold prayer meetings in that room as well. The truly unique aspect of these times that the family set apart for religious observances is that their slaves were invited and encouraged to participate in them alongside the family.
There still hangs on display an original piece of artwork in the Family Parlor that illustrates the significance of religion to the family. On the East wall of the room is a large painting of The Virgin Mary and the Christ Child, painted by a cousin of Mrs. Custis, Captain Williams. Even as a young man, Williams was said to be an accomplished artist. The prodigy saw the original of this painting while in Italy during the 1830s. Impressed, he copied it meticulously and then presented it to the Custis family upon his return to the United States. Most likely because this room was the focal point of the family's religious lives, it was accordingly hung in the Family Parlor.
Mrs. Custis and her daughter, Mrs. Lee, had very strong opinions on slavery—the most controversial issue of the time period—which would later change the course of the Lee family's life. Their opinions on slavery (along with their opinions on most everything) were primarily influenced by their religious convictions. Christianity teaches that all human lives are important and should thus be valued equally. This belief then affected the way that the family interacted with their slaves.
Despite the fact that it was illegal to educate slaves, Mrs. Custis and Mrs. Lee gave their own the opportunity to learn to read and write. The common belief of other Virginians was that slaves would become too independent if instructed how to read, and that education might lead to an insurrection; but the women of Arlington felt that it was much more important for their slaves to be able to read the Bible for themselves than for the family to be concerned about over-educated slaves.
These beliefs even impacted the slaves' schedules. Every Sunday afternoon, after the family attended services around 10am, Annie and Agnes Lee would hold Sunday school classes for the slave children in the dressing room connected to their bedroom. Mr. and Mrs. Custis also instructed that a chapel be built for their slaves not too far from Arlington House itself. The building was originally intended to serve as a school building for the slaves, but Mr. Custis received no response to his request to hire a school teacher. Instead of letting the building sit unused, Mrs. Custis had it used as a chapel for the slaves of Arlington and any others interested in attending services. The spirituality of her slaves was so important to Mrs. Lee that when she and Robert were at Fort Monroe—where the couple was stationed immediately after their marriage—and their slave Cassie was not allowed in the chapel on base, Mrs. Lee decidedly held Sunday school for the girl at home.
Mary Anna Custis began to strengthen her religious commitment in the summer of 1830, shortly after her engagement to Robert E. Lee. It was a very emotional experience for her. While grateful for her new position in respect to God, she also experienced a large amount of internal conflict. She felt that she was undeserving of this newly discovered grace; her sinful nature was much more apparent to her during this time as she often lamented about her worldliness and vanity. A journal that she began during her engagement period very eloquently describes Mary's religious beliefs and feelings, highlighting her constant desire to be more obedient to God.
She was confirmed on October 5th, 1831. Her new religious outlook on life highlighted her fiancé's lack of religious fervency. In several journal entries, Mary worries about Robert's spirituality and the fact that at this point religion was not as important to him as it was to her. Mary once wrote to Robert: “That God may protect & bless you & above all things may turn your heart to Him is my unceasing prayer for you.” Devotedly, Mary prayed that her husband would have a spiritual awakening similar to hers until one July day in 1853.
On July 17 of that year, Lee was confirmed by the Reverend John Johns at Christ Church with two of his daughters, Mary and Annie, alongside. Lee's decision to be confirmed was a joyous, relieving answer to the many prayers his wife had prayed over the course of twenty years. From that point on there was a marked difference in the way that Lee made life decisions. With firm conviction, Lee began to pray and read his Bible daily. He began to go to church regularly—a routine that his religiously committed mother had ingrained in him from day one. Now, as a grown man with grown children of his own, religious beliefs impacted his decisions not only in his personal life but in his military career and during his tenure as a college president as well. He “had come to [Washington College in] Lexington as much a missionary as an educator.” Lee weighed his decisions in light of the question: "what was his duty as a Christian and a gentleman?" Truly, his creed of doing that duty was acted upon even in the most challenging of social situations.
Religion was a very powerful force in the lives of the men and women that lived in Arlington House through much of the nineteenth century. Individually as well as collectively, their beliefs guided their interactions with their slaves and aided them in making almost any kind of decision. Any thorough examination of the lives of the Custis and Lee families cannot ignore the fact that, without their religious beliefs, they would have been a very different family remembered in a very different way.
 John Perry, Lady of Arlington, Multnomah Publishers, 2001, 87-8
 John Perry, Lady of Arlington, Multnomah Publishers, 2001, 74.
 Charles P. Roland, Reflections on Lee, Stackpole Books, 1995, 24.
 Douglas Southall Freeman, Lee, Macmilan Publishing Company, 1961, 564.
 Douglas Southall Freeman, Lee, Macmilan Publishing Company, 1961, 586.