H 277 - Saad has narrated from Ahmad bin Muhammad bin Isa and Muhammad bin Husain bin Abil Khattab from Hasan bin Mabub from Ali bin Raab from Ubaidullah bin Ali Halabi that:

I heard Imam Ja’far Sadiq say: “After divine revelation descended on the holy being of the Holy Prophet (s), he stayed in Holy Mecca for thirteen years. For three years of this period, he propagated Islam secretly and did not openly announce his prophethood till Almighty Allah commanded him to announce it. After that he publicized it.”