There are a multitude of reasons for the congregation to sing new songs. To make things clear: "new" in this case is a chronological category. Some of the very old songs such as were mentioned last week might well be new to your congregation, but that's not what we're talking about here. We really do mean "newly created hymns," and just for some sort of line we'll make "new" equivalent to the last forty years or so, which is a pretty quick little blip in the church's history. What may perhaps be interesting about the reasons to be discussed here (and again, there are plenty more) is that some are exactly the same or very similar to the reasons given to sing something old.
We can, for one thing, sing really, really new songs. Forget the corporate conglomerates grinding out "worship songs" on a perpetual basis. An event can happen, such as one of the mass shootings that have occurred over the past two years. A pastor and hymn writer, moved by the event, pens a poem and adjusts the text to fit with a well-known hymn tune. In the past, the next step might be distributing to her church and maybe others nearby, and otherwise waiting weeks or months or years for an opportunity for publication. Now? Thanks to the internet, that hymn can be available for churches to sing by the following Sunday.
Is that not as cool as being able to sing from Synesius of Cyrene? I mean, sing along with Hamilton: how lucky we are to be alive right now...
Others of the points from last week also repeat themselves. Hymns that span "every time and place"? Hello, "now" is included in that (and we'll have more to say about the "place" part of that formula too).
Also, if to refuse the older repertory of the church is to be "aloof and utterly separated from the church and its heritage," then to refuse those new hymns and songs is no less to be aloof and utterly separated from the church and its present. Bless Synesius's soul, he could have barely imagined the kinds of things both amazing and horrible that beset this world today, and you might imagine anything he wrote down would be strikingly different today.
Last week's reversible caveats also apply here;
1. Not everything that is sung should be new. (Obviously, after last week's post.)
2. Not everything that is new should be sung. If anything, new hymns and songs require even more exercise of discernment and critical observation, if only because fewer eyes have had the opportunity to look them over. Particularly given the rapid pace at which new songs are ground out in some genres, quality control isn't always a given (is my bias showing? Oh well...), and taking the time to give such new stuff a good theological frisking is simply a matter of basic integrity.
(Other note: it may not always be a theological reason that a hymn ultimately turns out to be a bad fit. I can think of one hymn of recent vintage that is theologically strong, musically interesting, and even kinda popular as new hymns go, but that I can never imagine placing before a congregation I lead.)
Depending on what kind of church you are, a good hymnal is still a possibility for obtaining such "new stuff" at least for a while. Remembering that the forty-year mark was pretty arbitrary, those denominations or other entities that haven't given up on the making of hymnals (in whatever format they may be distributed) can do a good job of both issuing an initial "new hymnal" and then following it up, if they so choose, with "hymnal supplements" with new material (or even recovered old material, or material that has never entered into the particular tradition of that hymnal), again whether hard copy or electronic or whatever hybrid comes along. If they choose to do so, that is.
Some basic principles apply; use your church's choir to help the congregation catch on to the song if need be, if the tune is familiar -- at minimum make sure that they are ready to sing the hymn strongly to help those who might be struggling. And be prepared to sing it strongly yourself.
So yeah, sing something old, and sing something new -- within the lifetime of a large part of your congregation. Don't be a separatist. Sing, sing with all the ancients and all our fellow sisters and brothers in Christ right here and now, and remember who we are, and where we are going.
My bias is showing: this hymnal does o.k. at including "new stuff."