أَخْبَرَنِي الْقَاسِمُ بْنُ زَكَرِيَّا بْنِ دِينَارٍ, قَالَ حَدَّثَنَا سَعِيدُ بْنُ شُرَحْبِيلَ, قَالَ أَنْبَأَنَا الَّيْثُ, عَنْ يَحْيَى بنِ أَيُّوبَ, عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرٍ, عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ, عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ, عَنْ حَفْصَةَ, عَنْ النَبِيِّ صلى الله عليه وسلمَ قَالَ " مَنْ لَمْ يُبَيِّتِ الصِّيَامَ قَبْلَ الْفَجْرِ فَلاَ صِيَامَ لَهُ " .

2333 Qasem Ibn Zakaria (RA) ... Umm al-Mu'minin Hafsa RA. He said, The Messenger of Allah, may God bless him and grant him peace, said - Whoever does not intend to fast before Fajr, his fast will not be complete.

Kitabus Sunan (Almujtaba) - Imam Nasa'i (Sunan Nasa'i)

Hadith No: 2331 International No: 2331

Tahqiq: pure (literally authentic)

Narrated by: Ummul Mu'minin Hafsa (RA) (Died: 41 Hijri)

Explanation of hadith:

Fasting is obligatory. Niyat means determination. As you will resolve in my heart, I am fasting for the coming days for the sake of Allah. It is not necessary to say it verbally. Hadith Sharif says, 'All actions depend on intention.'- Sahih Bukhari 1/2

It is better to do the intention of the obligatory fast while the night remains. Ummul Mu'mineen Hafsa RA. He said, The Messenger of Allah, may God bless him and grant him peace, said - من لم جمعة الصيام قبل الفجر فلا صيام له. Whoever does not intend to fast before Fajr, his fast will not be (complete). -Sunan Abu Dawud 1/333

If you can't make niyat at night, even if you make niyat before sunset during the day, it will become fast. Salama Ibnul Akwa RA. Said, (When the fast of Ashura was obligatory) the Messenger of Allah, may God bless him and grant him peace, asked a man from the tribe of 'Aslam to announce, 'He who has not eaten anything since morning will fast the rest of the day. And whoever eats it will also fast for the rest of the day. Because today is Ashura-Day.'-Sahih Bukhari 2007

Abdul Karim Jazari said, some people testified to see the moon in the morning. Then Umar Ibn Abdul Aziz. He said, 'One who has (already eaten something) will refrain from eating for the rest of the day. And whoever did not eat, he will fast for the rest of the day.'-Muhalla 4/293

It is not enough to commit Niyat together for the whole of Ramadan; Instead, the intention of each fast should be done separately. Because each fast is a different act (worship). And it is important to make a plan for each period. Hadith Sharif says, 'All actions depend on intention.'-Sahih Bukhari 1/2

See also: Almuhalla 4/285

Even if you intend to fast at night, you have time to eat and drink and have sex with your wife until dawn. It will not harm the intention. Allah Ta'ala says,

احل لكم ليلة السيام الرفث الى نسايكم

It is lawful for you to lie down with your wife during the night of Ramadan. - Surah Baqarah: 187

Niyat time starts from sunset of the previous day. For example, fasting on Tuesday can be done from the night before Monday, i.e. after sunset, it is not enough to fast on Sunday before sunset on Monday. Because, in the Hadith Sharif, it is said to do Niyyat at night.

# Collected

Fasting is a prerequisite for it to be Sahih, without Niyyat, fasting will not be pure. However, it is not obligatory or necessary to pronounce it orally or to say it in Arabic. It will be enough to have only this word in my mind that I am fasting.

If you can't make niyyat at night, even if you make niyyat about an hour before the sun sets during the day, it will become fast.

Even if you intend to fast at night, you have time to eat and drink and have intercourse with your wife until dawn. It will not harm the intention or fasting.