Fasting: Establishing the First of the Month by the Ruling of a Fully Qualified Jurist
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1700
The first of the month is not established by the ruling of a fully qualified jurist (al‑ḥākim al‑sharʿī) unless by means of his ruling, or the first of the month being established in his view, one derives confidence in the moon having been sighted.