Granny Weatherall was jilted at the alter by George. She waited for George and he never showed up. On her deathbed, she waits for Hapsy and a sign from God or Jesus that this is her time and she will be accepted into Heaven. At the end of the story, Granny is still waiting for a sign from God or Christ that she is headed for eternal bliss. But she recognizes no such sign.

This is the pattern she has been unable to break from: waiting for a male or paternal figure. Just as she waited for George, she waits for Christ. One could argue that this is a classic confusion God's signs. Granny is waiting for St. Michael or Jesus or some angel (presumably male) to meet her, take her to Heaven, and, fittingly, make amends for her earlier jilting. But the sign God sends is the vision of Hapsy, a woman. Granny recognizes this in her semi-conscious state but doesn't really grasp that the vision of Hapsy is this sign of salvation. "It was Hapsy she really wanted."

Here is the passage about the vision:

She had to go a long way back through a great many rooms to find Hapsy standing with a baby on her arm. She seemed to herself to be Hapsy also, and the baby on Hapsy's arm was Hapsy and himself and herself, all at once, and there was no surprise in the meeting.

There is Hapsy with a baby, continuing the cycle of life. Then she momentarily becomes Hapsy with a baby who is also Hapsy and still Granny. This metaphysical and spiritual connection between mother-daughter-son should bewilder Granny but it "was no surprise in the meeting." The son could be a reference to the son of God. So, this reunion (as a vision) with Hapsy and her son or "The Son" is loaded with spiritual signs and suggestions. (It should be noted that in many interpretations of this story, Hapsy is dead, having died in childbirth.)

So, the vision of meeting seeing/being reunited with Hapsy and the "son" (Christ) is a clear foreshadowing of being reunited in the afterlife: the real meeting to redeem her first jilting.

When Granny sees Hapsy, Hapsy "melted from within and turned flimsy as gray gauze and the baby was a gauzy shadow." Granny is dying—her life force is essentially melting away from within. Likewise, she'll be passing into the shadow realm soon, and people who had passed on before her may have felt like they'd been waiting for her forever, like Hapsy says she has been. Granny's "light" will fade at the story's end as Hapsy's does here.