Charles Ellicott Commentary Zechariah 1:16

"Therefore thus saith Jehovah: I am returned to Jerusalem with mercies; my house shall be built in it, saith Jehovah of hosts, and a line shall be stretched forth over Jerusalem." — Zechariah 1:16 (ASV)

A line. —To measure, and mark out its confines. (Compare to Zechariah 2:1-2.)