I heard this story many times in the 1940s, 50s, and 60s, recounted my Dad Charlie Hall Cavel, and uncles Arthur and Dick Cavel. It must have taken place when Charlie was 14 or 15 years old, so 1917 or 1918.
Charlie, Arthur and Dick were driving a herd of cattle from Velma (OK) to the rail head at Chickasha (OK). One evening they had corralled the cows and camped for the night. After a while they heard singing and shouting and, being naturally curious, they went to see what was going on.
Well, from some distance they could see a group of 30-40 people having a religious meeting under a brush arbour, lit by torches on poles stuck in the ground a few feet from each corner of the arbour. So the boys climbed a big tree just beyond the reach of the torch light and watched as the preacher worked his congregation into a fervor of religious enthusiasm. The worshippers became more and more energized under the influence of "The Spirit".
Soon they were running up and down the aisles, jumping the plank benches, throwing their arms in the air, imploring in loud voices, "Come Lord Jesus! Come Lord Jesus!"
Accustomed to the sedate dignity of the Baptist service, this hullabaloo struck the boys as comical, and they saw the opportunity to have some fun. They began to shake the limbs and branches of the tree. Arthur, who was about 20 years old at the time, lowered his voice as deep as he could and shouted down from the tree, "I'm a comin'! I'm a comin'!"
On hearing this announcement the worshippers began to scream and scattered into the night, including the preacher. Not a one waited to welcome the coming of the Lord.
If their father (who was a Baptist pastor) had ever learned of this stunt he'd have soundly whipped them all. I'm betting they didn't tell it openly until after Granddad's death in 1941, but while I was growing up they repeated the story again and again as evidence of what scoundrels they had been as teenagers.