In the Dutch Reformed Church in which I was raised, we sang this hymn to the melody of O Come All Ye Faithful. Then it was like getting an extra Christmas. But try as I might, I just can’t find any melody for How Firm a Foundation other than the one used here.
I think our hymnal said this was originally an old Portuguese hymn, but maybe my memory’s at fault. Be that as it may, give God the glory.
Very edifying! I try to get to worship service early so I can read the words of the hymns we are scheduled to sing (great poetry) because when I am actually singing them I have to concentrate on the notes more so than the words.