Forty years indicates the length of time that God cared for his people in the wilderness. In contemporary English it is normal to use a preposition with the time here, for example, “Through forty years” (Good News Translation), “for forty years” (Contemporary English Version, New Jerusalem Bible), or “During forty years” (Revised English Bible). New English Bible says it poetically with “Forty years long.”

Didst thou sustain them means to care for them. The next clause explains the full meaning of God’s sustaining them, that is, the fact that they lacked nothing. All their basic needs were provided. Good News Translation combines the two clauses into one that includes both the fact of God’s providing for them and the fact that all their needs were met, and some translators will find it helpful to follow this example.

Wilderness: See verse 19 above.

Their clothes did not wear out and their feet did not swell: Not only did God provide food and water, but he also cared for their material needs and for their health. They could wear the same clothes for forty years and their feet did not swell with pain or blisters (Deut 8.4). “Their shoes didn’t wear out” in an earlier version of Contemporary English Version was evidently based on the statement in Deut 29.5 that refers to both clothes and shoes, but the Hebrew word used in both this verse and Deut 29.5 refers to garments, so translators should not follow that example. In some languages translators may say that their clothes did not become torn or that the cloth did not become weak because of wear. Translators should observe the parallelism in this verse where the statement in the first part is exemplified in the second part.

Quoted with permission from Noss, Philip A. and Thomas, Kenneth J. A Handbook on Nehemiah. (UBS Helps for Translators). New York: UBS, 2005. For this and other handbooks for translators see here .