Thy
thy
–pronoun
the possessive case of thou (used as an attributive adjective before a noun beginning with a consonant sound): thy table.
thou
,pronoun, singular, nominative thou; possessive thy or thine; objective thee; plural, nominative you or ye; possessive your or yours; objective you or ye; verb
–pronoun


Thy will be done……It is a very formal way of speaking. It reminds me a little of the Shakespearean poetry. The old English usage from hundreds of years ago seems to equate more respect somehow, so therefore it remains here in the prayer.
Have you heard the prayer spoken aloud with the word “your” in place of the “thy”?

Our Father who art in heaven, hallowed be your name. Your kingdom come, Your will be done…. Somehow it loses a bit of the respectful nature of the prayer. It seems all of a sudden that the Father is a buddy of ours. Not that that in itself is a bad thing. Familiarity breeds comfort. But sometimes comfort breeds self-ish-ness. It is just lacking a little when it comes to the respectful nature that the prayer has otherwise.

Our Father who art in heaven,
Hallowed be your name.
Your kingdom come,
Your will be done.

It starts to sound a bit like a rap song to me too. It could be a song that others would relate to more readily. Perhaps it would.

As for me, I think I’ll keep the “thy”.