Al-Maaida 5:107

If they are found guilty [of false testimony], let two others take their place, nearest in kin from among those who claim a lawful right, and let them swear by Allah, “Our testimony is more truthful than their testimony, and we have not transgressed, for then we would surely be among the wrongdoers.”

But if it is found that those two were guilty of sin [i.e., perjury], let two others stand in their place [who are] foremost [in claim] from those who have a lawful right. And let them swear by Allāh, "Our testimony is truer than their testimony, and we have not transgressed. Indeed, we would then be of the wrongdoers."

107. If then it gets known that these two had been guilty of sin, let two others stand forth in their places, nearest in kin from among those who claim a lawful right. Let them swear by Allâh (saying): "We affirm that our testimony is truer than that of both of them, and that we have not trespassed (the truth), for then indeed we should be of the wrong-doers."

But then, if it is afterwards ascertained that both of them merit (the suspicion of) sin, let two others take their place of those nearly concerned, and let them swear by Allah, (saying): Verily our testimony is truer than their testimony and we have not transgressed (the bounds of duty), for them indeed we should be of the evil-doers.