We can pray any time; why hold our hands in certain ways, and why stand during some prayers but kneel during others? Prayer is communication with God, and body poses or hand gestures can lend expressiveness to the conversation. In private prayer, they are optional, but in community prayers like the Mass, they become an intrinsic part of the rite. Each body or hand position says something different.
The main body postures are standing, kneeling, sitting, and lying prostrate. Lying prostrate is not used in the rubric of weekly Masses, but it has its place in special rites like the Rite of Ordination. It recognizes human unworthiness, but also appeals to God’s mercy and submits us to His will. A similar effect is made by kneeling, which is used several times in the Mass and also in penitential contexts. It serves as the principal gesture of reverence.
By contrast, standing demonstrates confidence, and as Christians, we are meant to be confident in God’s love for us and in our place in His adoptive family. Sitting is more passive, but it can be used to signify attentiveness or contemplation.
Most commonly, we “fold” our hands during prayer. This term actually refers to two separate positions which are used fairly interchangeably. The position that interlaces the fingers suggests a more introspective posture, and possibly a more fervent frame of mind. When the palms are together and the fingers are straight, it suggests purity and evokes an act of homage. Indeed, an examination of medieval art will show this same gesture being used in an act of homage from a vassal to his lord. These can be used whether one is kneeling, sitting or standing. The organs pose, with arms outstretched and palms up, is a third gesture that really only works in the standing position.
It is the oldest gesture in common use today, based on historical descriptions and depiction in art. In the Mass and other community prayers, it has traditionally been used by the priest when he prays on behalf of the assembly, and in the Our Father. Its adoption by the laity has its origins in the charismatic movement.
In the end, remember that God hears our prayers regardless of the position of our hands or body. Posture can add to the conversation, and in the Mass, we in the laity have our own parts to perform as a community.