Language:
كتاب الجهاد والسير
56  
Fighting for the Cause of Allah (Jihaad)
(197)
Chapter: What to say on returning from Jihad
(197)
باب مَا يَقُولُ إِذَا رَجَعَ مِنَ الْغَزْوِ
Sahih al-Bukhari 3084

Narrated `Abdullah:

When the Prophet (ﷺ) returned (from Jihad), he would say Takbir thrice and add, "We are returning, if Allah wishes, with repentance and worshipping and praising (our Lord) and prostrating ourselves before our Lord. Allah fulfilled His Promise and helped His Slave, and He Alone defeated the (infidel) clans."

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا جُوَيْرِيَةُ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ إِذَا قَفَلَ كَبَّرَ ثَلاَثًا قَالَ ‏ "‏ آيِبُونَ إِنْ شَاءَ اللَّهُ تَائِبُونَ عَابِدُونَ حَامِدُونَ لِرَبِّنَا سَاجِدُونَ، صَدَقَ اللَّهُ وَعْدَهُ، وَنَصَرَ عَبْدَهُ، وَهَزَمَ الأَحْزَابَ وَحْدَهُ ‏"‏‏.‏
Reference : Sahih al-Bukhari 3084
In-book reference : Book 56, Hadith 288
USC-MSA web (English) reference : Vol. 4, Book 52, Hadith 317
  (deprecated numbering scheme)