I got this from (I think) Jimmy Akin.
During the Last Supper, the Lord said to his disciples, "***Do this in memory of me***." In Greek, this statement reads, "*Touto poieite eis tan eman anamnesin*." There are two aspects of this phrase that deserve consideration. For one, the phrase *touto poieite *can be translated as *do this *or as *offer this. *In the Old Testament, God commands the Israelites "***you shall offer*** (*poieseis*) ***upon the altar two lambs***" (Ex. 29:38). This use of *poiein *is translated as *offer this *or *sacrifice this *over seventy times in the Old Testament. So the same word that is used for the sacrifice under the Old Covenant is used for the sacrifice of the Mass in the New.
The second key aspect of this phrase is Our Lord’s use of the word *anamnesin. *If you were to ask someone to look in a Greek Translation of their Bible, every time this word (anamnesis) appears it is within a sacrificial context, such as in Numbers 10:10, “…you shall blow the trumpets over your holocausts and your peace offerings; this will serve as a reminder of you before your God. I, the LORD, am your God". It also can be translated as *memorial offering *or memorial sacrifice. While these nuances are lost in the English translation, Jewish ears would have understood the sacrificial meaning of Christ’s words.
It seems that the words were used in a priestly context.
Hence we have ordination.