Here was a song in the night. And the singer sings, not of a broken heart, but a fixed heart. The darkness has not dimmed his vision, has not quenched the light of faith in his soul. He feels deeply the anguish and bitterness of the night, but his heart holds firm and steadfast.

According to the superscription, this song was sung by David at the time he was fleeing from Saul, hiding in the cave. The circumstances are those of very great trial and difficulty. But there is no wavering of his confidence. In the dark he believes in the light. His heart fixed—fixed upon God. With his heart fixed upon God, he is able to sing and give praise, in spite of all that might make sobs and tears choke the song and silence the note of praise in his heart.

Some have their hearts fixed, but fixed upon earth. And when the little spot of earth upon which they have built their confidence and hope is shaken, they are shaken; their confidence and hope are shattered, and the song of cheer they sang so gaily a while ago is turned into a sob of complaint and despair.

It is easy to sing when the sun is shining. It is easy to be cheerful when flesh is comfortable and prosperity is spreading its bright sky over our heads, but it is another matter when our circumstances are altered and disappointment clouds our sky.

To keep our heart singing when the cloudy day comes, it must be made calm and steadfast by faith in something more stable than earthly circumstances.

The only man who can sing and give praise in times of darkness, is the man who can say, “My heart is fixed, O God, my heart is fixed.”

The trials and sorrows we experience in the night seasons of life make this fixed heart hard to keep. It is hard to keep up our faith when all is dark about us. It is hard to hold on to our confidence when we are shut up in a cave. How can we do it? David did it through prayer: “Be merciful unto me, O God, in the shadow of Thy wings will I take refuge, until these calamities be overpast” (v. 1). Prayer is the secret of keeping a fixed heart and keeping in the heart a song in the night.