43. The faithful should stand from the beginning of the Entrance chant, or while the priest approaches the altar, until the end of the Collect; for the Alleluia chant before the Gospel; while the Gospel itself is proclaimed; during the Profession of Faith and the Prayer of the Faithful; from the invitation, Orate, fratres (Pray, brethren), before the Prayer over the Offerings until the end of Mass, except at the places indicated below.
They should, however, sit while the readings before the Gospel and the responsorial Psalm are proclaimed and for the Homily and while the Preparation of the Gifts at the Offertory is taking place; and, as circumstances allow, they may sit or kneel while the period of sacred silence after Communion is observed.
But they should kneel at the consecration, except when prevented on occasion by reasons of health, lack of space, the large number of people present, or some other good reason. Those who do not kneel ought to make a profound bow when the priest genuflects after the consecration.
Nevertheless, it is up to the Conference of Bishops to adapt the gestures and postures described in the Order of Mass to the culture and reasonable traditions of the people. The Conference, however, must make sure that such adaptations correspond to the meaning and character of each part of the celebration. Where it is the practice for the people to remain kneeling after the Sanctus until the end of the Eucharistic Prayer and before Communion when the priest says Ecce Agnus Dei (This is the Lamb of God), this practice is laudably retained.
With a view to a uniformity in gestures and postures during one and the same celebration, the faithful should follow the directions which the deacon, lay minister, or priest gives according to whatever is indicated in the Missal.