This has been an issue under heated debate.
In my parish, joining hands together while saying the Lord's Prayer is a common practice. While some second the practice based on the argument that it originates from and imitates the 'oran/orantes' in the early Church, I hold reservations towards this. The following are my reasons:
Joining hands by the laymen may result in confusion of the sacerdotal role of the priest. When the priest stretches out his hands (manibus extensis), he is in fact a living icon of a crucified Christ on the Cross, representing Jesus in the execution of the sacred liturgy. When the faithful join their hands, the implied finger-bending (digitis flexis) action is an explicit contradiction to what is required of the priest as a living icon by the our liturgy.
Joining hands by the laymen may cause misconceptions in the expression of affection in liturgy. According to the Rituale Romanum, joining hands is an expression of love in a couple exclusive to the exchange of rings in nuptial liturgy. Hence, misconceptions regarding the symbolic implications of liturgical postures may arise when the faithful, who are not in the context of matrimonial rituals, join their hands in a Mass.
The Congregation for Divine Worship in 1975 published the Notitiae which criticised joining hands as a posture introduced individually when no clear instruction in Missale Romanum has been mentioned. Since liturgy should be an open confession of faith by the Church as a community, such practice of private devotion or out of personal fervor should never be encouraged. On the other hand, the faithful should be encouraged to do what is necessitated in Missale Romanum instead of availing themselves of the grey area.
Caeremoniale Episcoporum, in articles discussing liturgical postures, mentioned the following:
'104. Consuetudo est in Ecclesia Episcoporum aut presbyterorum orationes ad Deum dirigere stantem, et manus aliquantulum elevatas et extensas tenentem. ...]'
Thus, it is apparent that stretching hands, or similar actions as joining hands, are assumed to be the privilege of priests. Symbolically, it is an action exhibiting the priest as the executor of liturgy 'in persona Christi capitis'.
- The Missale Romanum never expects the faithful and deacons to imitate the priest to stretch out their hands:
'... Neither may deacons or non-ordained members of the faithful use gestures or actions which are proper to the same priest celebrant ... (Article 6, Instruction on Collaboration, 1997)'
On the grounds of the above reasons,joining hands, or mimicking the priest's stretching hands in any other way, may engender obfuscation in terms of liturgical symbolism. Thus, joining hands while saying the Lord's Prayer should not be encouraged.