It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) once, while residing in Madinah Munawwarah—not while traveling—combined (the seven rak‘ahs of Maghrib and ‘Isha) and (the eight rak‘ahs of Zuhr and ‘Asr) and prayed them together.
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 1929
Hadith Gradingحکم دارالسلام:صحيح لغيره، خ: 1174، م: 705. وهذا إسناد ضعيف، محمد بن عثمان الجمحي ضعيف.