Invocation
To the debtor when his debt is settled
بارَكَ اللهُ لَكَ في أَهْلِكَ وَمالِك، إِنَّما جَـزاءُ السَّلَفِ الْحَمْدُ والأَداء
May Allah bless you in your family and your wealth, surely the reward for a loan is praise and returning (what was borrowed).
An-Nasa'i, 'Amalul-Yawm wal-Laylahp. 300, Ibn Majah 2/809. See also
Al-Albani, Sahih Ibn Majah2/55.