Kitāb al-Ghayba

Hadith 195
occultation
وكان المرتضى رحمه الله يقول أخيرا لا يمتنع أن يكون هاهنا أمور كثيرة غير واصلة إلينا هي مودعة عند الإمام عليه السلام وإن كان قد كتمها الناقلون ولم ينقلوها ولم يلزم مع ذلك سقوط التكليف عن الخلق لأنه إذا كان سبب الغيبة خوفه على نفسه من الذين أخافوه فمن أحوجه إلى الاستتار أتى من قبل نفسه في فوت ما يفوته من الشرع، كما أنه أتى من قبل نفسه فيما يفوته من تأديب الإمام وتصرفه من حيث أحوجه إلى الاستتار ولو زال خوفه لظهر فيحصل له اللطف بتصرفه وتبين له ما عنده مما انكتم عنه فإذا لم يفعل وبقي مستترا أتى من قبل نفسه في الأمرين،وهذا قوي تقتضيه الأصول.
Sayyid Murtadha (r.a) lately said that it is possible that there may be many things that have not reached us and are entrusted with the Imam and the narrators have concealed them. However, it does not follow that people are not bound by these religious duties. Because if the reason for the occultation is his fear for his life from those who have threatened him, the ones who have forced him into hiding are ultimately responsible for the missed teachings of the Imam and his leadership, as they forced him into occultation. And should these people stop threatening him, he will appear and the grace of his leadership will materialize and the teachings he has to offer will manifest. Therefore, he has not caused this occultation of religious teachings. However, if the enemies do not end the fear and it continues, they are responsible for both cases. This argument is strong and supported by principles.
Source: Shaykh Muḥammad b. al-Ḥasan al-Ṭūsī