He held this ground strongly when the general view of the Bible was narrower than of late years. As the years went on he grew broader and sweeter, feeling wider sympathy with all true, devout religious belief.
He was a constant church-goer, everywhere. When traveling he always made Sunday a resting-day if possible, and would go quietly off in the morning to find some place of service, in English if he could. He enjoyed the Episcopal service, though early habit and training had made him a Presbyterian; but, as he wrote in an early letter, “In fact I have no more fondness for high Calvinistic theology than for German neology.... But I have no penchant for melancholy, sober as I sometimes look, but turn always, like the leaves, my face to the sun.”
He was a teacher in Sunday-schools in New York (the lady with whom he boarded has still a lively remembrance of his enthusiastic study of German that he might teach his class of German boys better), and also in his early years of Cambridge life, until the heavy load of work he was carrying made the Sunday more imperative as a day of rest. It was his rule to rest on Sunday. Rest for him was change of intellectual occupation, and he read all of the day he was not out at church; more especially on the philosophical questions, whether general or scientific, which next to botany were his chief interest. Books on these subjects were the few he bought outside of works on botany; as he said, he could only afford botanical books and had no money or room for general literature. He read the leading magazines, and occasionally biographies and travels, and if he had friends staying with him, Sunday was the day for talk and discussion. A friend writes such a lively reminiscence of one of these Sunday discussions, on a stormy winter day which shut all in the house, that it seems worth giving as a vivid description of him.
“Dr. Gray is more associated with the study and the room next it, but I recall him there (in the parlor) also, especially in the visit of which you wrote, made when Mr. John Carey was with you. He and the doctor held one Sunday a long discussion on the Ten Commandments as binding upon Christians. Mr. Carey argued that their only claim upon our obedience consisted in their having been re-ordained (indorsed as it were) by the church,--whether that meant the Holy Catholic or simply the Anglican Church was not decided, as I remember. Dr. Gray combated this extreme church view warmly and cleverly. Both were pugnacious amiably, as in their botanical fights. Both were excited, and the doctor showed his excitement in his characteristically self-forgetful way, by moving or jumping nervously about the room, sitting on the floor, lying down flat, but laughing and sending sparks out of his eyes, and plying his arguments and making his witty thrusts all the while. I enjoyed it very much, scarcely observing the odd positions any more than the doctor did. I had seen him so conduct himself before.”