Jami` at-Tirmidhi 198
Bilal narrated:
"Allah's Messenger said [to me]: 'Do not say the Tathwib for any prayer except the Fajr prayer.'"

[He said:] There is something on this topic from Abu Mahdhurah.
Abu `Eisa said: We do not know of the Hadith of Bilal except as a narration of Abu Isra'il Al-Mula'i. Abu Isra'il did not hear this Hadith from Al-Hakam bin `Utaibah.

He said: He only reported it from Al-Hasan bin `Umarah, from Al-Hakam bin `Utaibah. Abu Isra'il's name is [Isma`il bin Abi Ishaq, and he is not strong according to the people of Hadith.

The people of knowledge have differed over the interpretation of At-Tathwib.

Some of them say that At-Tathwib is when one says "As-Salatu Khairummin An-Nawm, (prayer is better than sleep)" for the Adhan
of Fajr. This is the saying of Ibn Al-Mubarak and Ahmad.

Ishaq said something different about At-Tathwib, he said: "[The disliked Tathwib] is something that the people started after the Prophet; when the Mu'adh-dhin
calls the Adhan and the people are slow in coming, so between the Adhan and the Iqamah he says:
'Qad Qamatis-Salat, Hayya `Alasalat, Hayya `AlalFalah. (Prayer is ready, come to prayer, come to success.)"

[He said:] This Tathwib, which Ishaq mentioned, is the one that the people of knowledge dislike, which they innovated after the Prophet.

But Ibn Al-Mubarak and Ahmad explained that At-Tathwib is when the Mu'adh-dhin says: "As-Salatu Khairum minan-Nawm, (prayer is better than sleep)" for the Adhan of Fajr.
And this is the correct saying, and it is called At-Tathawwub as well, and this is the one chosen by the people of knowledge, and it is their opinion.

It has been reported from `Abdullah bin `Umar that he would say: "As-Salatu Khairum-minan-Nawm, (prayer is better than sleep)" for Fajr.

It has been reported from Mujahid that he said: "I entered a Masjid with `Abdullah bin `Umar in which the Adhan was called, and we wanted to pray in it. Then the Mu'adh-dhin said the Tathwib. So `Abdullah bin `Umar left the Masjid and said: 'Let us leave the place of this innovator' And he did not pray in it."

[He said:] `Abdullah only disliked the Tathwib that the people invented later on.
حَدَّثَنَا أَحْمَدُ بْنُ مَنِيعٍ، حَدَّثَنَا أَبُو أَحْمَدَ الزُّبَيْرِيُّ، حَدَّثَنَا أَبُو إِسْرَائِيلَ، عَنِ الْحَكَمِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، عَنْ بِلاَلٍ، قَالَ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ لاَ تُثَوِّبَنَّ فِي شَيْءٍ مِنَ الصَّلَوَاتِ إِلاَّ فِي صَلاَةِ الْفَجْرِ ‏"‏ ‏.‏ قَالَ وَفِي الْبَابِ عَنْ أَبِي مَحْذُورَةَ ‏.‏ قَالَ أَبُو عِيسَى حَدِيثُ بِلاَلٍ لاَ نَعْرِفُهُ إِلاَّ مِنْ حَدِيثِ أَبِي إِسْرَائِيلَ الْمُلاَئِيِّ ‏.‏ وَأَبُو إِسْرَائِيلَ لَمْ يَسْمَعْ هَذَا الْحَدِيثَ مِنَ الْحَكَمِ بْنِ عُتَيْبَةَ قَالَ إِنَّمَا رَوَاهُ عَنِ الْحَسَنِ بْنِ عُمَارَةَ عَنِ الْحَكَمِ بْنِ عُتَيْبَةَ ‏.‏ وَأَبُو إِسْرَائِيلَ اسْمُهُ إِسْمَاعِيلُ بْنُ أَبِي إِسْحَاقَ وَلَيْسَ هُوَ بِذَاكَ الْقَوِيِّ عِنْدَ أَهْلِ الْحَدِيثِ ‏.‏ وَقَدِ اخْتَلَفَ أَهْلُ الْعِلْمِ فِي تَفْسِيرِ التَّثْوِيبِ فَقَالَ بَعْضُهُمُ التَّثْوِيبُ أَنْ يَقُولَ فِي أَذَانِ الْفَجْرِ الصَّلاَةُ خَيْرٌ مِنَ النَّوْمِ وَهُوَ قَوْلُ ابْنِ الْمُبَارَكِ وَأَحْمَدَ ‏.‏ وَقَالَ إِسْحَاقُ فِي التَّثْوِيبِ غَيْرَ هَذَا قَالَ التَّثْوِيبُ الْمَكْرُوهُ هُوَ شَيْءٌ أَحْدَثَهُ النَّاسُ بَعْدَ النَّبِيِّ صلى الله عليه وسلم إِذَا أَذَّنَ الْمُؤَذِّنُ فَاسْتَبْطَأَ الْقَوْمَ قَالَ بَيْنَ الأَذَانِ وَالإِقَامَةِ قَدْ قَامَتِ الصَّلاَةُ حَىَّ عَلَى الصَّلاَةِ حَىَّ عَلَى الْفَلاَحِ ‏.‏ قَالَ وَهَذَا الَّذِي قَالَ إِسْحَاقُ هُوَ التَّثْوِيبُ الَّذِي قَدْ كَرِهَهُ أَهْلُ الْعِلْمِ وَالَّذِي أَحْدَثُوهُ بَعْدَ النَّبِيِّ صلى الله عليه وسلم ‏.‏ وَالَّذِي فَسَّرَ ابْنُ الْمُبَارَكِ وَأَحْمَدُ أَنَّ التَّثْوِيبَ أَنْ يَقُولَ الْمُؤَذِّنُ فِي أَذَانِ الْفَجْرِ الصَّلاَةُ خَيْرٌ مِنَ النَّوْمِ وَهُوَ قَوْلٌ صَحِيحٌ وَيُقَالُ لَهُ التَّثْوِيبُ أَيْضًا وَهُوَ الَّذِي اخْتَارَهُ أَهْلُ الْعِلْمِ وَرَأَوْهُ ‏.‏ وَرُوِيَ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ أَنَّهُ كَانَ يَقُولُ فِي صَلاَةِ الْفَجْرِ الصَّلاَةُ خَيْرٌ مِنَ النَّوْمِ ‏.‏ وَرُوِيَ عَنْ مُجَاهِدٍ قَالَ دَخَلْتُ مَعَ عَبْدِ اللَّهِ بْنِ عُمَرَ مَسْجِدًا وَقَدْ أُذِّنَ فِيهِ وَنَحْنُ نُرِيدُ أَنْ نُصَلِّيَ فِيهِ فَثَوَّبَ الْمُؤَذِّنُ فَخَرَجَ عَبْدُ اللَّهِ بْنُ عُمَرَ مِنَ الْمَسْجِدِ وَقَالَ اخْرُجْ بِنَا مِنْ عِنْدِ هَذَا الْمُبْتَدِعِ ‏.‏ وَلَمْ يُصَلِّ فِيهِ ‏.‏ قَالَ وَإِنَّمَا كَرِهَ عَبْدُ اللَّهِ التَّثْوِيبَ الَّذِي أَحْدَثَهُ النَّاسُ بَعْدُ ‏.‏