The text was printed in Adin Ballou, 1849, no. 231. Falchion is in verse 4 as well.
Compiled by Adin Ballou, 1849, "The Hopedale Collection of Hymns and Songs, for the Use of Practical Christians," Hopedale, Mass., Hopedale Press, A. A. Ballou, Printer.

Ballou cites himself as author of the hymns-songs that are his. He did not do so with this poem, so the author was not known to him- it is not by Ballou.

231 .... P. M.
(No author or title cited)

1
Years are coming- speed them onward!
When the sword shall gather rust,
And the helmet, lance and falchion,
Sleep in silent dust!
2
Earth has heard too long of battle,
Heard the trumpet's voice too long;
But another age advances,
Seers fortold in song.
3
Years are coming when, forever,
War's dread banner shall be furled
And the angel Peace be welcomed,
Regent of the world!
4
Hail with song that glorious era,
When the sword shall gather rust,
And the helmet, lance and falchion,
Sleep in silent dust!

In the Introduction, Ballou says, "I found it so difficult to trace out the authorship of many hymns, that a considerable number are left uncredited." That is true of this hymn. He continued, "Many variations and supposed improvments have crept into hymns of the best authors. ....Ballou says that he has himself modified some of the texts.
No author or title cited for this song.

On line; find by googling: The Hopedale Collection of Hymns and Songs:

(I have some old books of songs and quotations- I'll take a look on the offchance that I can find the author).