The Bishop of Gloucester Rt Revd Rachel Treweek - who also became the first female bishop to sit in the chamber, last October - read from Psalm 46.
Speaking about God as "refuge and strength", the Psalm also says: "Therefore we will not fear, though the earth give way and the mountains fall into the heart of the sea, though its waters roar and foam and the mountains quake with their surging."
Rt Revd Rachel Treweek spoke to Premier before stepping into the House of Lords. She said: "Although I am aware this is making history, what I try and keep my heart and mind focused on is: This is about me being fully who I am and, as a follower of Jesus Christ, doing what I feel I have been called to do."
Sittings in the House of Lords and the House of Commons begin with Christian prayers, with members of each chamber attending on a voluntary basis.
Rt Revd Rachel Treweek added: "I can only be who I am and I believe that what I am doing, by taking up this role, is becoming the person God has created me to be, which is what I want to encourage every person to be."