I say, and with God's success: It is disliked for the retreating worshipper to remain silent believing it to be an act of worship, and it is prohibited. However, silence for rest is not disliked; as narrated by Ali ibn Abi Talib (may Allah be pleased with him), I heard from the Messenger of Allah (peace be upon him): 'There is no completion after a wet dream, nor silence from day until night.' This is found in Sunan Abu Dawood 3: 115, Sunan Al-Bayhaqi Al-Kabir 6: 57, Al-Mu'jam Al-Awsat 1: 95, and Al-Mu'jam Al-Saghir 1: 169. Al-Haythami said in Majma' Al-Zawa'id 4: 334: Its narrators are trustworthy. Refer to: Sharh Ibn Malik Q65/A, Sharh Mulla Maskin p. 73, Al-Mabsut 3: 122, and Al-Tabyin 1: 351, and Allah knows best.