Scripture readings and standing

Would you please explain how the readings are chosen for service? Why are some readings from the Old and others the New Testament? How come we only stand for the "gospel"? Shouldn't we stand for all the readings because it is the "word of the Lord"? Thank you for your response!!!

Probably most of our churches use the schedule of Scripture readings that you will find on pages 163-166 of Christian Worship: A Lutheran Hymnal. Pages 163-165 list the Scripture readings over a three-year cycle. We are currently in “Year A” (page 163). Page 166 lists an annually-repeated schedule of Scripture readings.

Christian Worship: Manual, the “handbook” for our hymnal, provides an explanation for worshipers standing for the reading of the gospel: “The congregation stands for the reading of the Gospel. In the past soldiers put down their weapons and kings removed their crowns when the Gospel was read. Christ—his life, his words of law and gospel, his suffering, his death, his resurrection, his ascension, his assignment to his Church, his promise to return—is the center of the Gospel. The faithful have waited for this moment, this reading. They stand in reverence. ” (pages 173-174)

Through the gospel lesson Jesus—the Word (John 1), the Word of God (Revelation 19:13)—comes to us. The gospel lesson relays the words and works of Christ. For those reasons, we have retained an ancient practice of showing respect and awe for the Lord and his gospel by standing. That practice of course falls into the category of adiaphora: those things that God has neither commanded nor forbidden. In Christian freedom, we gladly include that posture in our liturgy—as we are able.