Sahih Bukhari Volume 2, Book 18, Hadith 1110

حَدَّثَنَا أَبُو الْيَمَانِ، قَالَ أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي سَالِمٌ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم إِذَا أَعْجَلَهُ السَّيْرُ فِي السَّفَرِ يُؤَخِّرُ صَلاَةَ الْمَغْرِبِ، حَتَّى يَجْمَعَ بَيْنَهَا وَبَيْنَ الْعِشَاءِ‏.‏ قَالَ سَالِمٌ وَكَانَ عَبْدُ اللَّهِ يَفْعَلُهُ إِذَا أَعْجَلَهُ السَّيْرُ، وَيُقِيمُ الْمَغْرِبَ فَيُصَلِّيهَا ثَلاَثًا، ثُمَّ يُسَلِّمُ، ثُمَّ قَلَّمَا يَلْبَثُ حَتَّى يُقِيمَ الْعِشَاءَ، فَيُصَلِّيهَا رَكْعَتَيْنِ، ثُمَّ يُسَلِّمُ وَلاَ يُسَبِّحُ بَيْنَهَا بِرَكْعَةٍ، وَلاَ بَعْدَ الْعِشَاءِ بِسَجْدَةٍ حَتَّى يَقُومَ مِنْ جَوْفِ اللَّيْلِ‏

Narrated By Az-Zuhri : Salim told me, "'Abdullah bin 'Umar said, 'I saw Allah's Apostle delaying the Maghrib prayer till he offered it along with the Isha prayer whenever he was in a hurry during the journey.' " Salim said, "Abdullah bin Umar used to do the same whenever he was in a hurry during the journey. After making the call for Iqama, for the Maghrib prayer he used to offer three Rakat and then perform Tasllm. After waiting for a short while, he would pronounce the Iqama for the 'Isha prayer and offer two Rakat and perform Taslim. He never prayed any Nawafil in between the two prayers or after the 'Isha prayers till he got up in the middle of the night (for Tahajjud prayer)."