God’s law specifies that at least two or three witnesses are required to establish guilt in a court of law. One witness, one person’s word, is not enough to convict anyone. Throughout the Bible, important points are reiterated. For example, the Ten Commandments are listed twice. Hundreds of scriptures are given two or more times.
We need to use that principle in our own lives, not believing and acting upon something because of only one person’s statement. It is a principle that God the Father and Jesus Christ have established and use, even though They are perfect and without fault. They still use two witnesses.