For many Christians this hymn has another tune. But in the church I grew up in, which no longer exists, How Firm a Foundation was sung to the tune of a Christmas carol, O Come, All Ye Faithful.
This, above, is the only example of it I could find. Yes, it’s only a piano playing. There is something to be said for simplicity: I believe the Lord likes it.
So find a magnifying glass for the lyrics, and sing along.