Elizabeth,
Thanks for the kind words, but I can't take full credit for knowing this. An
Armenian Orthodox friend, who posts with me on several forums, recently asked the same question on OC.net (probably to add the info to his wonderful website). Given a bit of time, I would have come up with what he needed, but the combined efforts of a few of us there pulled it together in no time.
John,
Actually, most historians agree that the finger configurations trace back to early times in all of the Apostolic Churches and were used as a means of demonstrative teaching/reminder of various theological truths - much as tradition says that Holy Patrick used the shamrock to illustrate the Trinity.
Erini,
Very nice explanation of the reasons for the right to left usage by the Copts and other Oriental Churches.
Mina,
The usage by the Latin Catholics was originally right to left, as is done by the Eastern Orthodox. In fact, Pope Innocent III, in the thirteenth century, explicitly directed that it be done right to left. For the Latins, the change occurred as a result of the congregation mirroring the actions of the priest as he blessed them. In the Oriental Churches, though, the usage appears to have always been left to right.
For those who bless themselves right to left, one explanation is that the right shoulder was touched first because the Son sits at the right hand of the Father, and the right represents good while the left represents evil. Erini's explanation of the Copt reason for left to right is essentially that put forth by all the Oriental Churches.
Not sure who asked about the conformation of the fingers, but for almost all it involves the thumb and first two fingers joined to represent the Trinity, with the last two fingers curled into the palm to suggest the two Natures. However, the Ethiopians (and, I think the Eritreans as well) do the obverse, joining the index finger to the thumb to indicate the One Incarnate Nature and bending the other three to symbolize the Trinity.
I don't think anyone has mentioned it (and I beg the indulgence of my Copt brethren in speaking for their traditions) but I am also aware of a traditional Copt practice of signing solely with the thumb. Although not common, I understand that it is still done by some - I have no idea what the significance is of doing so.
Just as a matter of interest, the Russian Old Believers or Old Ritualists don't use the Trinitarian invocation in signing themselves; rather, they recite the Jesus Prayer.
Many years,
Neil