Open Psalm 135. In your English Bible it is 136, for the reason I explained in the article on Psalm numbering.

Alleluia. Give thanks to the Lord: for he is good: for his mercy endures for ever.

(Psalm 135:1)
Theologians Bible

Now read the rest of the psalm. That second half comes back at the end of every single verse. All the way down. The whole history of creation and the Exodus, and after each line, the same refrain hammered home.

For his mercy endures for ever.

The word behind "mercy" is one of the great words of the Old Testament, and English has never managed to carry it in one piece.

The word

In Hebrew it is חֶסֶד, chesed. Open the Hebrew Lexicon and look at how many English words get used for it across the translations. Mercy. Lovingkindness. Steadfast love. Covenant faithfulness. Loyalty. Goodness. Grace.

Those are not synonyms in English. They pull in different directions. Mercy suggests pity from above. Lovingkindness suggests warmth. Steadfast love suggests endurance. Covenant faithfulness suggests a contract kept.

chesed is all of that at once, and this is why translators keep swapping words. They are not being sloppy. They are trying to keep whichever strand matters most in that particular sentence.

What holds it together

Here is the thing that ties the strands into one word.

chesed is love that has obligated itself and then keeps the obligation, even when the other side has not.

It is not raw sentiment, because sentiment does not endure. It is not mere contract, because a contract ends when the other party defaults. It is loyal love. Love that has bound itself, and stays bound, and keeps showing up.

Now read the refrain again with that in your ears. For his chesed endures forever. The endurance is not an add on. The endurance is the point. God has bound Himself to a people who broke the terms constantly, and He does not walk away.

What the Septuagint did with it

This is where it gets interesting for us, because the Church did not read this psalm in Hebrew. She read it in Greek.

Look at the Greek line under the verse:

Ἐξομολογεῖσθε τῷ Κυρίῳ, ὅτι ἀγαθὸς, ὅτι εἰς τὸν αἰῶνα τὸ ἔλεος αὐτοῦ.

ἔλεος. The translators reached for the Greek word for mercy, for pity, for compassion shown to someone in need.

And now say Kyrie eleison. Lord have mercy. Same root. That word, which you say more than any other word in the Divine Liturgy, is the word chosen to carry chesed into Greek.

So when you ask for mercy, you are not asking a judge to reduce a sentence. You are asking the God who bound Himself and never once walked away to keep doing what He has always done.

That changes the prayer. Kyrie eleison is not grovelling. It is appealing to a track record.

Something is lost, and it is worth knowing

I have argued in these articles that the Church is right to read the Greek, and I stand by that. But I am not going to pretend nothing is lost in the move.

ἔλεος is a narrower word than chesed. It carries the mercy and the compassion beautifully. It does not carry the covenant loyalty as loudly. The Hebrew word has a spine of obligation in it that the Greek word does not emphasise in the same way.

This is not a scandal and it is not evidence of corruption. It is what happens whenever anything is translated. Something is always left at the border. The honest reader knows this and goes looking for what was left.

That is exactly why both texts are on the screen, and why there is a Hebrew lexicon on this site as well as a Greek one. Not so you can play the traditions against each other, but so that you can see the whole word.

How to study it

According to your great mercy. Not according to my performance. According to the thing in God that endures forever whether or not I have earned it.

That is the word. And you sing it every week.