I give you a new commandment - Peter Aston. Published by RSCM, I think. 2-part + org. Easy and effective.

PGA, doesn't Tallis have a companion pieceto "If Ye Love Me?" that uses that text above? I have it in my library, but I'm not there. I think CPDL might have it.

My Church of Christ friends sing an a capella contrapuntal piece with the "Love One Another" text. Very pretty- but it might be too American-folk-music for you. You want I should track it down?

This video has a decent recording. It's called "The Greatest Commandment.
The video says the music is "Traditional," but other places have it listed as by Janice Detweiler.

The video says it's available from Howard Publishing, but I couldn't find it (I looked for about 2 minutes, though...)

It's 4 part, but very easy. I learned it sitting on a living room floor without music.


(By the way, y'all- When I talk about a legitimate place for contemporary/folk/pop music in the Sacred Liturgy, this is the sort of thing I'm talking about. You might still dislike, or disagree, but at least now you'll know I don't really mean this awfulness)

CPDL #18172:
PGA/Adam et al,
This is the one to which I earlier referred. It is a thematic companion to "If Ye Love Me," as we've performed it a couple of times in the last few years in proximity to the more familiar piece; almost like the Pars secunda of SICUT CERVUS.

Editor: Rod Mather (submitted 2008-10-23). Copyright: Personal

CPDL #6947:
Editor: Michael Gibson (submitted 2004-04-20). Score information: A4, 6 pages, 236 kbytes Copyright: Personal
Title: A new commandment
Composer: Thomas Tallis

Number of voices: 4vv Voicing: SATB
Genre: Sacred, Anthem

Language: English
Instruments: Optional organ which doubles the voices

Original text and translations
English text

A new commandment give I unto you, saith the Lord,
that ye love together, as I have loved you,
that e'en so ye love one another.
By this shall ev'ry man know that ye are my disciples,
if ye have love one to another.

Noel,

That will work wonderfully; Thank you very much.

ALL composers should seriously look at writing more SAB music. I know many choirs of that makeup, some, like mine, are pretty decent, and can handle "real" reperatoire, but just don't have the men for SATB.

SAB is tricky since most theory teachers want you to understand 4 part writing and therefore, little or no time is spent on three part writing.

Thanks, PGA, it was fun to write. My wife's choir will be singing it as well in a few weeks, have a guest soprano, alto and baritone coming from a choir I once led into extinction, that Sunday.

Theory teachers... agh!
As if we are all going to spend the rest of our musical lives writing Protestant Hymns.

FNJ
YES!
I know it would take a little longer, and some students would be bored, but serious music theory instruction (especially for choral and composition majors) should mirror the development of music theory itself.
One of my goals in life is to take a couple years off to re-learn music the way I wish I had been taught it in the first place.

Maybe we could start a school.

I have no doubt that, like all groups of people, there are standouts.
I just wish the average trended a little better.

And actually, my problem is more with methodology- it was not the fault of any one of my theory teachers that the matriculation for theory went:
-four-part chorale writing
-more four-part chorale writing
-some more four-part chorale writing
-how to turn four-part chorale writing into a formulaic keyboard accompaniment
-oh, yeah, if you want to learn anything else, that's an elective at an inconvenient time, and you can't take it until you get through two years of four-part chorale writing.

As I have often find myself thinking about Episcopalian music, my interests include both the very much older and the very much newer, but not so much that in particular.

Yeah yeah, you don't have to rub it in.

CC, you are a trip.

I would go with "You are near." The last thing you need while falling out of the sky is more gravitas.

University music professors: what a foul breed! :-)

Harmony exercises are meant to get a student in tune with the common practice of tonal music, not to create great composers.

Practically all music theory is an ex post facto, or inductive, description: what was done, not what one should or should not do. Learning about theory, therefore, is really learning about history. The amazing thing? Even the Medieval theorists were writing about a practice, not necessarily prescribing rules.

Music theory curricula, I might add, are built around practicality. Most music students are working in a common practice idiom most of the time. It's as simple as that. I've said it on this board before, but there are prominent theorists, and even some textbooks, that take the "historical lineage" approach described by other posters above.

Neither of these is an "ideal" version of what you're looking for, but if you piece together what they have to offer, you can get a lot out of both:

Felix Salzer, Structural Hearing
Steven Laitz, The Complete Musician

The caveat is that both of these are intended for the study of tonal harmony, so they skip a lot of concepts pertinent to chant, like modes. Their approach takes the Renaissance as its jumping off point and goes from there.

The interesting thing about their way of thinking is that harmony is a byproduct of interweaving melodic lines, not a strictly vertical phenomenon. Focusing primarily on Roman numerals and figured bass symbols really inculcates the idea that music is made up of several vertical columns moving left to right in time, and these authors don't see it that way.