Albert Barnes Commentary Ezekiel 47:4

"Again he measured a thousand, and caused me to pass through the waters, waters that were to the knees. Again he measured a thousand, and caused me to pass through [the waters], waters that were to the loins." — Ezekiel 47:4 (ASV)

The knees - The mission of Paul and Barnabas (Acts 13:1–4) is another marked epoch in the Church’s history; and the time of Paul’s martyrdom denotes an increase in the Gentile Church, which corresponds with the waters reaching the loins.