Hamilton v. Russell

But

were unanimously of opinion that the possession, or the probability that his brother would suffer him to remain in possession, was not such an interest as affected his competency, but went only to his credibility. (See the other points of this case in the report of it in the supreme court of the United States, 1 Cranch [5 U. S.l 309, where the judgment of this court was affirmed.)

[The question of the competency of the witness does not seem to have been raised in the supreme court.]