Some people leave a small part of the night to ensure that they fasted the entire day
Machine translationRead the Arabic original
The questioner : May Allah bless you. Is it correct for a scholar to say that a person should leave a small part of the night to ensure that he fasted the entire day?
The Shaykh : No, this is very weak. This statement is weak, because the text says "until it becomes clear." If it were obligatory to abstain from a part of the night, it would have said "until it approaches."
The questioner : This means the end of a part of the day of Ramadan.
The Shaykh : Yes. "Until it becomes clear," but if it becomes clear, he stops. Yes.
The Shaykh : No, this is very weak. This statement is weak, because the text says "until it becomes clear." If it were obligatory to abstain from a part of the night, it would have said "until it approaches."
The questioner : This means the end of a part of the day of Ramadan.
The Shaykh : Yes. "Until it becomes clear," but if it becomes clear, he stops. Yes.
Source
قناة «فضيلة الشيخ محمد بن صالح العثيمين»، 2075 - بعض الناس يترك جزءاً يسيراً من الليل لكي يتحقق أنه صام النهار كله - ابن عثيمين — youtube.com
The Arabic text is a machine transcription of the audio recording.