The hand gesture is a secret sign indicating that the gentleman is a Marrano – a crypto-Jew who accepted Christian baptism in order to remain in Spain after the Catholic Kings' order of 1492 that all Jews leave Spain;
The gesture indicates a Loyolan/Jesuit spirituality that calls for the sinner to place his/her hand on their chest after committing a sin as a sign of moral pain. Both of these theories have been discussed at length in academic circles without, however, formal acceptance of either, though at least one academic allows that the hand "assumes the function of an important communication, a personal avowal."
San Ignacio de Loyola, who founded the Jesuits by approval of Pope Paul III in 1539, came from a "Marrano" family…The hand sign term "Marrano" is a Spanish expression which means "secret Jew", i.e. a falsely converted Jew. Therefore, on the one hand, Ignatius Loyola displayed an outward show ofIgnatius Loyola devotion but in dramatically contradictory fashion…appears to have been a member of "Alumbrado" which was a forerunner to the Illuminati organization (the word "Alumbrado" is simply a Spanish translation for the term "Illuminati")