1800/1 - ‘Ali (may Allah be pleased with him) reported: “I memorized this from the Prophet (may Allah’s peace and blessings be upon him) as he said: ‘There is no orphanhood after reaching puberty, and there is no silence for the whole day till the night.’” [Narrated by Abu Dāwūd with a sound Isnād]
Commenting on this Hadīth, Al-Khattābi said: “One of the rites in the pre-Islamic period of ignorance was silence. So, they were prohibited in Islam from doing so and were commanded to remember Allah and speak good.”
1801/2 - Qays ibn Abu Hāzim reported: “Abu Bakr al-Siddīq (may Allah be pleased with him) visited a woman from the Ahmas tribe, called Zaynab, and he noticed that she was not speaking. So, he asked: ‘Why is she not speaking?’ They said: ‘She has intended to perform Hajj without speaking.’ He said to her: ‘Speak, for this is unlawful; it is a practice of the pre-Islamic period of ignorance.’ Thereupon, she spoke.” [Narrated by Al-Bukhāri]
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1) It is obligatory to differ from the people of the pre-Islamic period of ignorance in terms of their deeds and conditions. So, it is not permissible for a person to worship Allah by keeping silent till night because this is not part of the Islamic guidance.
2) If a person makes a vow to be silent, his vow should not be fulfilled, for it is a vow of sin and not a valid one.
‘Ā’ishah (may Allah be pleased with her) reported that the Messenger of Allah (may Allah’s peace and blessings be upon him) said: “Whoever makes a vow to obey Allah should obey Him; and whoever makes a vow to disobey Allah should not disobey Him.” [Narrated by Al-Bukhāri]