Testimony that is invalidated in part is invalidated entirely.
Bava Kama, fol, 73, col. 1.
Let witnesses know with whom and before whom they bear testimony, and who will one day call them to account; for it is said (Deut. xix. 17), "Both the men between whom the controversy is shall stand before the Lord."
Sanhedrin, fol. 6, col. 2.
Those that eat another thing (i.e., not pork, but those who receive charity from a Gentile.—Rashi and Tosefoth) are disqualified from being witnesses. When is this the case? When done publicly; but if in secret, not so.
Ibid., fol. 26, col. 2.
He who swears falsely in a capital case is unreliable as a witness in any other suit at law; but if he has perjured himself in a civil case only, his evidence may be relied upon in cases where life and death are concerned.
Ibid., fol. 27, col. 1.
He who disavows a loan is fit to be a witness; but he who disowns a deposit in trust is unfit.
Shevuoth, fol. 40, col. 2.