Ask thee a sign of the LORD thy God; ask it either in the depth, or in the height above.
Ask thee a sign of (literally, from with-Hebrew, mee`im (H5973 ); Chaldaic, from the face of) the Lord thy God - since thou dost not credit the prophet's words.
A sign - a miraculous token, to assure thee that God will fulfill His promise of saving Jerusalem (Isaiah 37:30; Isaiah 38:7-8). 'Signs,' i:e., miraculous facts then present or near at hand, as pledges for the more distant future, are frequent in Isaiah.
Ask it either in the depth - literally, make deep, ask it; i:e., go to the depth of the earth or of Hades (Vulgate), or, mount high for it (literally, make high). So in Matthew 16:1. Signs in heaven are contrasted with the signs on earth and below it (raising the dead) which Jesus Christ had performed (cf. Romans 10:6-7). He offers Ahaz the widest limits within which to make his choice.