When He (sal-Allaahu 'alayhe wa sallam) used to receive pleasant news, He (sal-Allaahu 'alayhe wa sallam) would say:

الْحَمْدُ لِلَّهِ الَّذِي بِنِعْمَتِهِ تَتِمُّ الصَّالِحَاتُ

Praise is to Allah Who by His blessings all good things are perfected.

Alhamdu lillaahil-lathee bini'matihi tatimmus-saalihaat.

And if something happened that displeased him, he used to say:

الْحَمْدُ لِلَّهِ عَلَى كُلِّ حَالٍ

Praise is to Allah in all circumstances.

Alhamdu lillaahi 'alaa kulli haal.

Ibn As-Sunni, 'Amalul-Yawm wal-Laylah, and Al-Hakim who graded it authentic 1/499. See also Al-Albani, Sahihul-Jami' As-Saghir 4/201.