John Gill Commentary 1 Kings 14:12

"Arise thou therefore, get thee to thy house: [and] when thy feet enter into the city, the child shall die." — 1 Kings 14:12 (ASV)

Arise you therefore, get you to your own house
With all haste, as soon as she could:

and when your feet enter the city ;
the city of Tirzah, very probably the king's palace stood at the entry of it, see (1 Kings 14:17) ,

the child shall die ;
this is an answer to the question she was to ask, and at the same time a token of the sure and certain fulfilment of all the prophet had spoken in the name of the Lord.