The Kitáb-i-Aqdas - The Most Holy Book
Index term: of witnesses (legal), under Testimony
k67.
It hath been decreed by God that, should any one of His servants intend to travel, he must fix for his wife a time when he will return home. If he return by the promised time, he will have obeyed the bidding of his Lord and shall be numbered by the Pen of His behest among the righteous; otherwise, if there be good reason for delay, he must inform his wife and make the utmost endeavour to return to her. Should neither of these eventualities occur, it behoveth her to wait for a period of nine months, after which there is no impediment to her taking another husband; but should she wait longer, God, verily, loveth those women and men who show forth patience. Obey ye My commandments, and follow not the ungodly, they who have been reckoned as sinners in God's Holy Tablet. If, during the period of her waiting, word should reach her from her husband, she should choose the course that is praiseworthy. He, of a truth, desireth that His servants and His handmaids should be at peace with one another; take heed lest ye do aught that may provoke intransigence amongst you. Thus hath the decree been fixed and the promise come to pass. If, however, news should reach her of her husband's death or murder, and be confirmed by general report, or by the testimony of two just witnesses, it behoveth her to remain single; then, upon completion of the fixed number of months, she is free to adopt the course of her choosing. Such is the bidding of Him Who is mighty and powerful in His command.
n99.
two just witnesses
Bahá'u'lláh sets out "the criterion of justness" in relation to witnesses as "a good reputation among the people". He states that it is not necessary that the witnesses should be Bahá'ís since "The testimony of all God's servants, of whatever faith or creed, is acceptable before His Throne" (Q&A 79).
q79.
 
Question: Concerning the criterion of justness when proving some matter dependent on the testimony of two just witnesses.
Answer: The criterion of justness is a good reputation among the people. The testimony of all God's servants, of whatever faith or creed, is acceptable before His Throne.