أَسْتَوْدِعُ اللَّهَ دِينَكَ وَأَمَانَتَكَ وَخَوَاتِيمَ عَمَلِكَ
Astawdi'ullaha dinaka wa amanataka wa khawatima 'amalik
I entrust to Allah your religion, your trust, and the conclusion of your deeds.
Dua said by the traveler for the one staying behind
Mutual dua between traveler and resident is from the sunnah.