Having received the Most Sacred Body, and meditated for a few moments, one genuflects and rises, saying:
What reward shall I give unto YHWH for all the benefits that he hath done unto me? I will receive the Cup of Salvation and call upon the Name of YHWH.
At a very early point in Christian history, these words were appropriated to the Cup of the Lord's Blood; in the 'Anamnesis' of the Roman Canon the priest offers Calicem salutis perpetuae (I am by no means convinced of the correctness of the assumption that the form given by S Ambrose - Calicem vitae aeternae - is earlier). Perhaps the author of the psalm had in mind the (fourth) Cup "of Blessing" in the Passover Meal; a rabbinic commentary on the psalm says: "I will elevate the chalice of salvation; that is, when I keep festival and rejoicings, I will lift up a cup of wine, I will give thanks to Him over it in the presence of many, and will make mention of the salvation wherewith He has saved me." And the probability is that this psalm (116:10ff/115) was part of the Hallel said by the Lord and His disciples on Maundy Thursday Night; in the Western Rite it is part of Vespers on Maundy Thursdsay and Good Friday.
I will offer unto thee the sacrifice of thanksgiving and will call upon the Name of YHWH; I will pay my vows unto YHWH in the sight of all His people; in the courts of the House of YHWH, even in the midst of thee, O Jerusalem.
Anglican committees, when composing Eucharistic Prayers that Protestants will not object to, get a lot of headway out of phrases like "Sacrifice of praise and thanksgiving", which Protestants probably consider means "Sacrifice consisting of no more than praise and thanksgiving". The phrase in the Hebrew Bible, of course, means a sacrifice, consisting, like all sacrifice, of material oblata, which are offfered for a thanksgiving. One presumably thinks here of the Levitical thank-offering of fine flour; which means that this psalm, having mentioned the Chalice, has now alluded to the two Eucharistic Elements.
The same psalm was running through the mind of whoever composed the prayer Memento, probably originally said by the Deacon and referring to the elements which the offerentes had brought up to the Altar: "who offer unto thee this sacrifice of Praise ... who render their vows ...". These phrases have been integral to Eucharistic discourse from the Night before the Lord's Death until now.
I do not know if I have irritated anyone by introducing a reminder of the Tetragrammaton into Coverdale's translation. My purpose is to emphasise that we are Jews who ...
I think this post has gone on long enough. I hope to finish it tomorrow.