309. Condolence Dua for Death (Masnun Dua)
It is better to recite this dua in giving condolence
أَعْظَمَ اللَّهُ أَجْرَكَ، وَأَحْسَنَ عَزَاءَكَ، وَغَفَرَ لِمَيِّتِكَ
اَعْظَمَ اللّٰهُ اَجْرَكَ، وَاَحْسَنَ عَزَاءَكَ، وَغَفَرَ لِمَيِّتِكَ
A'dhamAllahu 'ajraka, wa 'ahsana 'azaa'aka wa ghafara limayyitik.
Translation
May Allah increase your reward, grant you the tawfiq of patience (in mourning), and forgive the dead person.