And when he opened it, all the people stood up.
Key moments
The faithful commonly stand for the Gospel because Christ is being proclaimed, for the Creed because the Church is confessing the faith, and for the Eucharistic prayers because the Church is approaching the holy mysteries. People may also stand when the priest enters with incense, when a blessing is given, or when the service turns toward the altar.
Oh come, let us worship and bow down; let us kneel before the Lord our Maker.
Standing also connects worship to the Resurrection. The Church stands before the risen Christ as people who are awake, attentive, and ready to receive His word. The body is being taught to share in the prayer of the Church.
Reverence with mercy
If you lose track, stand when most of the faithful stand. If your body needs rest because of illness, age, pregnancy, disability, exhaustion, or caring for children, sit without embarrassment. Reverence is honest attention to God, and the body learns worship with patience.
Local practice can vary, especially in long services. The deeper rule is to honor the holy moment with the strength you have.