Today is the feast of St. Isidore of Seville, Doctor of the Church. From his Etymologies, 6.19.38-42 (my translation):
The sacrifice [sacrificium] is said to be as it were a sacred act [sacrum factum] because by mystical prayer [prece mystica] it is consecrated [consecratur] to the memory of the Lord's suffering for us; thus at his bidding we call it the body and the blood of Christ, which, while it is made from the fruits of the earth, is sanctified [sanctificatur] and becomes a sacrament [fit sacramentum] by the Holy Spirit working invisibly [invisibiliter], of which sacrament [sacramentum] of bread and cup the Greeks call 'Eucharist', which is interpreted in Latin as 'good grace' [bona gratia]. And what is better than the body and blood of Christ? The sacrament [sacramentum] occurs in a celebration when a deed done is understood as to signify something that is received in a holy way [sancte]. And so baptism and chrism, body and blood, are sacraments [sacramenta]. These are called sacraments [sacramenta] because, under the bodily skin of the thing, the divine power secretly [secretius] works the salvation pertaining to those sacraments [sacramenta]; thus on the basis of secret power [secretis virtutibus] or sacred power [sacris] they are called 'sacraments'. These are fruitfully accomplished in the hands of the Church because the Holy Spirit dwelling in it works the effect of the sacraments [sacramentorum] in a hidden way [latenter]. Thus, whether they are dispensed within the church of God by good or bad ministers, still the Holy Spirit, who once appeared in the times of the apostles by visible works, mystically [mystice] vivifies them. These gifts are neither amplified by the merits of good dispensers nor attenuated by those of the bad, because (1 Cor 3:7) 'Neither is he that plants anything, nor he that waters, but God gives the increase.' Thus in Greek it is called 'mystery' [mysterium], because it has a secret [secretum] and concealed disposition.'Secretum' and its cognates are quite difficult to translate in contexts like this; 'secretum' literally means 'separated or set apart', but can also mean secluded, severed, rejected, excluded, nonobvious, confided, entrusted, private, hidden, personal, consecrated, and, of course (though less often than one might think), secret or clandestine. It's not surprising that Isidore interprets 'eucharist' as 'bona gratia', but it's interesting that he seems to interpret this as specifically indicating its value ("And what is better than the body and blood of Christ?"), so that the emphasis is on the 'bona'.
