One of the great hymns of the Protestant faith is Thomas Chisholm's Great is thy faithfulness. Its lovely words and music have led to it being sung all around the world.

The hymn speaks of God's great faithfulness to us, and of the beautiful witness of nature to him: "Summer and winter and springtime and harvest..."

There is "pardon for sin, and a peace that endureth", God's own presence, strength, hope and blessing. So, "Great is thy faithfulness..."

The hymn has blessed millions of people since it first appeared in 1923. But some people fear the hymn may not be that great after all.

The first line and the refrain are drawn from one of the most tragic of all Old Testament books, Lamentations. Two verses say: "Because of the Lord's great love we are not consumed, for his compassions never fail. They are new every morning; great is your faithfulness." (3:22-23)

So far, so good. But Chisholm, who served briefly as a Methodist minister before resigning due to ill health and becoming an insurance salesman, lifts the verses out of their context without acknowledging where they come from.

Lamentations is just that: a lament.

There's no particular reason to think it was written by Jeremiah, but it comes from the same situation: the onslaught on Jerusalem by the Babylonians in 587 BC. And this was dreadful. The country was devastated. Lamentations speaks of starving children (2:12), mothers eating their offspring (2:20), priests murdered at the altar, rape, torture and slavery (5:11-13).

There's nothing wrong with singing hymns of faith – and there's nothing really wrong with the theology of Chisholm's hymn.

But we lose something when we detach its words from their biblical location.

Great is thy faithfulness isn't just a general assertion of God's enduring goodness. It comes out of a deep trial, an experience of horror. God appears to have abandoned his people. Worse, he appears to have turned against them and be fighting alongside their enemies.

But in spite of this, the writer of Lamentations can express a profound faith that he will not desert them and that he has good purposes for them. It is no coincidence that these verses, so full of hard-won hope, are exactly in the middle of the book, and on either side there are more laments. It's in the middle of our trials that we have most need to be assured of God's faithfulness.

What would a truly biblically faithful version of Great is thy faithfulness look like? Its verses would be about the dark times in our lives – sin, sickness and sorrow. They would talk about war, injustice and hunger.

But the refrain would be exactly the same:

Great is thy faithfulness! Great is thy faithfulness!
Morning by morning new mercies I see;
all I have needed thy hand hath provided;
great is thy faithfulness, Lord, unto me!

And it would be an even more tremendous testimony to God's enduring love.

Follow Mark Woods on Twitter: @RevMarkWoods