Spiritual Retreat: The Intention and Duration of Iʿtikaf
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1724
A muʿtakif must have the intention of attaining proximity to Allah in the same manner that was mentioned regarding ablution (wuḍūʾ).[1] Iʿtikāf must be performed from start to finish with a sincere intention to attain proximity to Allah.
iv. The duration of the iʿtikāf must be a minimum of three days.
-Ayatullah Sistani, Practical Laws of Islam, Spiritual Retreat (Iʿtikāf)
1
See the sixth condition for the validity of wuḍūʾ and Ruling 281.