بارَكَ اللهُ لَكَ في أَهْلِكَ وَمالِك، إِنَّما جَـزاءُ السَّلَفِ الْحَمْدُ والأَداء
Baarakallaahu laka fee ahlika wa maalika, innamaa jazaa us-salafil-hamdu wal adaa .
May Allah bless you in your family and your wealth, surely the reward for a loan is praise and returning (what was borrowed).
Reference: An-Nasa i, Amalul-Yawm wal-Laylahp. 300, Ibn Majah 2/809. See also Al-Albani, Sahih Ibn Majah2/55.