Willard Richards note on how Joseph says one can detect false spirits.
Joseph Smith, Discourse, 1 May 1842, as Reported by Willard Richards, 94, The Joseph Smith Papers website, accessed July 18, 2023
preached in the grove on the keys of the kingdom charity &c.— The keys are certain signs & words by which false spirits & personages may be detected from true.— which cannot be revealed to the Elders till the Temple is completed.—
The rich can only get them in the Temple. The poor may get them on the Mountain top as did Moses.
The rich cannot be saved without cha[r]ity. giving to feed the poor. when & how God requires as well as building. There are signs in heaven earth & hell. the elders must know them all to be with power. to finish their work & prevent imposition. The devil knows many signs. but does not know the sign of the son of man. or Jesus.
No one can truly say he knows God until he has handled something. & these this can only be in the holiest of Holies