Narrated Ibn 'Umar: The Prophet 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.
— Sahih Bukhari, Volume 2, Book 26: Pilgrimmage (Hajj), Hadith #733