Imam Musa Sadr, with a broad and comprehensive Islamic approach, paid attention to all Islamic religions. Calling to Islam based on wisdom and good preaching was one of his strategic affairs. Imam Sadr considered religion as the principle and considered sect as the views and methods of Muslims. . In the late 1950s he moved to Lebanon, where he became involved in social work among the country’s largely disenfranchised Shiʿi community. In 1968–69 he formed the Higher Shiʿi Islamic Council to promote the community’s interests, and in 1975 he formed Amal, an armed wing of his Ḥarakat al-Maḥrūmīn (“Movement of the Deprived”), a Shiʿi social reform movement, in order to defend the Shiʿi community in the Lebanese Civil War.
He and a small entourage disappeared while on an official trip in Libya. The Libyan government disavowed any knowledge of what became of the cleric and his companions; his disappearance has remained a highly controversial mystery.
Imam Khomeini says about Imam Musa Sadr: I am sad at not seeing Mr. Mūsā Sadr among you. He was like my son. He was a strong arm of Islam.(Sahifeh-ye-Imam. V 15. P 5)