Each and every single thing in mass has significance. Every single movement, posture, word spoken, and thing done means something. The more you understand about what is going on in a Mass, the more you are able to appreciate its beauty.
The Sitting | Sitting is a posture of listening. Catholics sit for the first reading, the Psalm, and the second reading. We also sit for the offering, and the homily. We sit, ready to hear and receive. We sit to listen.
The Standing | For Prayer: Standing has been a posture of prayer for Jewish people since before the time of Jesus. Standing during prayer is also seen throughout different parts of the Bible. So, as Catholics, we continue to utilize this posture for prayer today.
Some examples of when we stand during Mass for prayer: When we pray the opening prayer, the Prayers of the Faithful, and The Lord's Prayer.
For the Creed. We stand as we say in unison what Christians have believed from the earliest times. We stand to affirm our unity and our beliefs together as Christians.
For the Gospel: Standing is also a sign of respect. We have many readings from the Bible during Mass, but we stand for the Gospel out of particular respect, since these are the words and deeds of Jesus himself.
For the Procession: We stand at the beginning and end of Mass, also as a sign of respect as the celebrant.
The Kneeling | Kneeling is a posture of respect and adoration. Another time when we kneel is during the preparation for and before/after reception of the Eucharist. We kneel, again, because we believe Jesus is fully and truly present in Communion. If you believed you were literally in the presence of Christ himself, falling to your knees would be a natural thing to do.
The postures of Mass can, likewise, reflect your state of mind, or it can help put you in the right one.If you come into Mass and you genuflect towards the tabernacle, because you are humbly acknowledging Christ's presence there, and if you sit, intent on listening with your mind, body, and soul, and if you stand, heart focused on prayer, and if you kneel acknowledging the presence of your Savior, then, then, you've got something.
As in all of the structures within Mass, and within Catholicism as a whole, there are so many tools to help move your heart, mind, and soul closer in relationship with Jesus.
Fr. Antonius David Tristianto, O.Carm.