Two phrases occurred to me while entering a post that I felt was probably not really going to add anything of value. The first was “teaching your grandmother to suck eggs”, which I have put on ewein’s “new posters” thread. The second was “a work of supererogation”, which I had always believed meant doing something that was unnecessary as it had been done already, but differently. The dictionary, however, gives it as a term used in the Roman Catholic Church and defines it as a contribution to a reserve fund of merit that can be drawn upon in favour of sinners (I take this to be a fund of good deeds or gladly suffered misfortune rather than a fund of money). This is so far from what I had believed that I am baffled. Please, can anyone help me out here?