The Holy Prophet (Sallallahu alaihi wa sallam) stopped the sermon for Imams, Hasan And Hussain (May Allah be well pleased with them)
There is a Hadith in Jame Tirmidhi. Sunan Abu Dawood and Sunan Nasai:
Translation: Hadhrat ‘Abdullah Bin Buraidah (May Allah be well pleased with him) says that he heard Hadhrat Buraidah (May Allah be well pleased with him) saying: The Holy Prophet (Sallallahu alaihi wa sallam) was giving a sermon. When Imam Hasan and Imam Hussain (May Allah be well pleased with them) came baby-walking, wearing red striped garments, the Holy Prophet (Sallallahu alaihi wa sallam) came down from the pulpit and lifted Hasan and Hussain (May Allah be well pleased with them). Then again stepped on to the pulpit and said: Allah has truly said that this world is a great test. I saw these kids walking ever so carefully; I could not stop myself, so much so that I stopped My Khutba and lifted them. (Jame’ Tirmidhi, Vol. 2, Pg No. 217, Hadith No: 3707; Sunan Abu Dawood, Hadith No: 935; Sunan Nasai, Hadith No: 1394; Zujajatul Masabeeh, Pg No. 333)
This Hadith reveals the deep relationship of the Holy Prophet (Sallallahu alaihi wa sallam) with Imam Hussain (May Allah be well pleased with him). In childhood, even their falling on the ground was not acceptable to the Holy Prophet (Sallallahu alaihi wa sallam).
The Holy Prophet (Sallallahu alaihi wa sallam) stopped the sermon, stepped down from the pulpit and lifted them. With this, the Holy Prophet (Sallallahu alaihi wa sallam) made this as clear as the day that they (Imam Hasan and Imam Hussain) themselves are the Deen, as the sermon cannot be stopped for worldly purposes. Then by describing their actions on the pulpit, He (Sallallahu alaihi wa sallam) made it as clear as the day every action of theirs is also a part of religion.