What is the best kind of petitionary prayer (dua) of a believer for another?
It is one in accordance with the conditions of its acceptability. A prayer is more or less acceptable in consideration of certain conditions being met. For example, when one prays to God for something, he should first cleanse himself by asking for forgiveness from God, and then call Gods blessing on the Prophet Muhammad as an intercessor before and after the prayer. For calling Gods blessing on the Prophet is an acceptable prayer and the prayer said between two acceptable prayers is usually acceptable also. In addition, such a prayer should be said in the absence of the believer for whom it is said and be the kind of the prayers mentioned in the Quran and Hadith. For example, one should prefer comprehensive prayers such as: O God, I ask forgiveness of You, for me and him, and soundness in religion, in this world and in the Hereafter! Our Lord, grant us in the world good, and in the Hereafter good, and guard us against the chastisement of the Fire! One should pray with sincerity, from t
