(96) باب مَنْ جَمَعَ بَيْنَهُمَا وَلَمْ يَتَطَوَّعْ
Narrated Ibn `Umar:
The Prophet (ﷺ) offered the Maghrib and `Isha' prayers together at Jam' (i.e. Al-Muzdalifa) with a separate Iqama for each of them and did not offer any optional prayer in between them or after each of them.
Reference: Sahih al-Bukhari 1673
In-book reference: Book 25, Hadith 153
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 26, Hadith 733