Rabanus Maurus : Mordecai prays with the Jews on behalf of Queen Esther, and the queen likewise prays for Mordecai and the Jews, because a teacher ought to offer prayers to the Lord on behalf of his students, and students on behalf of their teachers, that the entire community of the faithful—i.e. the limbs along with the whole body—may be kept whole through the kindness of Heaven. This explains why, when Paul writes to the Romans, he tells them that he constantly mentions them in his prayers; and he also makes these same Romans swear on the Lord Jesus Christ, and on the charity of the Holy Spirit, that they would help him in their prayers and pray for him to the Lord that he might be freed from the faithless who were in Judea, and that his ministry—which he was bringing to Jerusalem—might be acceptable to the saints. So too is it written in the Acts of the Apostles that when Peter was thrown in jail, the Church prayed constantly to the Lord on his behalf; and he himself likewise asks in his letter that the grace of God, and the peace of the Church, may be multiplied and fulfilled in the knowledge of our Lord Jesus Christ. — Commentary on Esther