The psalmist reflects on the brevity of life in Psalm 39:5. Other things are going on in the psalm, but I want to focus on a word in verse 5.
Behold, you have made my days a few handbreadths, and my lifetime is as nothing before you. Surely all mankind stands as a mere breath! (Psalm 39:5 ESV)
The word is handbreadth. A handbreadth is the width of your four fingers excluding your thumb or about 3 inches. The psalm has used a short measure of length to talk about length of time. I can visualize a handbreadth. It is harder to visualize time. But the psalm reminds me of the brevity of life.
This brings us to the cubit, which is a measure of length six times greater than a handbreadth or about 18 inches, the distance from the tip of your fingers to your elbow. Jesus uses the cubit in a discussion on worry.
Which of you by worrying can add one cubit to his stature? (Matthew 6:27 NKJV)
Translators have a bit of a struggle in this verse. The Greek word (ἡλικία | hēlikia | Strong’s G2244) can mean either a span of life or a reference to height. So which should we choose?
I think Psalm 39:5 tips the balance in favor of length of life. Jesus uses the very generous cubit in comparison to the handbreadths of the psalm. But I think both are using measurements of length to describe lengths of time. It is figurative not literal. They are striking images.
I’m also not convinced that most people wishing to be taller want to be 18 inches taller at least in the ancient world. Basketball was not a motivation in the time of Jesus. A person who is 5 foot 2 inches would become 6 foot 6 inches.
Translations understanding this is a reference to height are the KJV, NKJV, and HCSB. Translations understanding this as adding to the length of life are ESV, NASB, NIV, NET, and CSB. These latter translations change cubit to hour or moment with footnotes giving more information.
Psalm 39 reminds us of the brevity of life. It’s like handbreadths. Jesus instructs us that we can’t even add a cubit to our life spans length with worry.
— Russ Holden