As we are approaching the Feast of Trumpets/Yom Teruah I had to ask the question to myself:

Does it state in the Bible that two witnesses are needed to declare a new moon?

Well, the Bible does mention the importance of witnesses in the context of establishing various legal and religious matters, but it does not specifically state that two witnesses are needed to declare a new moon. The determination of the new moon in the Jewish calendar was traditionally done by the Sanhedrin, the Jewish high court, based on the sighting of the new moon by reliable witnesses.

The process of establishing the new moon involved the testimony of witnesses who had seen the thin crescent of the new moon, and the testimony of two witnesses was generally required for matters of this nature. However, the specific requirement of two witnesses for the declaration of the new moon may have been established through rabbinic interpretation and tradition rather than being explicitly stated in the Bible itself.

It's also important to note that different religious traditions and sects may have their own interpretations and practices related to the declaration of the new moon, and these practices can vary.

Since 2016, I've been monitoring the new moon sightings in Israel to determine the timings. Given our access to the internet while living in the diaspora, there's no excuse for not staying informed.