A series of prayers for use in this Sunday’s worship has been published by the Lutheran Church – Missouri Synod, including this collect, which is appropriate for so many occasions.
O Savior, our Good Shepherd, You taught us that the thief comes only to steal and to kill and to destroy, but that You have come to bring life in abundance. Remember in Your divine pity those who have endured the terror attack in Boston, and comfort them with Your presence and promises. Receive our thanks for the care provided by the first responders and all who have ministered to those suffering. Continue to grant to the afflicted Your healing and to those who mourn, grant the peace that can come only from Your victory over death. Thwart the desires of those who would sow fear and discord among us and lead them to repentance. We make these prayers to You in confidence, for You have known in Your own flesh the irrational hatred and violence and overcome them with divine compassion and love, You who live and reign with the Father and Holy Spirit, one God, now and forever. Amen.
All of the prayers are located on the LCMS Mercy Forever Blog