Moreover the LORD spake again unto Ahaz, saying, Ask thee a sign of the LORD thy God; ask it either in the depth, or in the height above. But Ahaz said, I will not ask, neither will I tempt the LORD. And he said, Hear ye now, O house of David; Is it a small thing for you to weary men, but will ye weary my God also? Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. - Isaiah 7:10-14 - KJV
In verse 3 of this chapter Isaiah is sent by the Lord to Ahaz to say things to him (v.4). In verse 10 the Lord speaks to Ahaz, presumably through Isaiah. In verse 13 we see "And he said" but it is unclear if this is Ahaz or Isaiah speaking for the Lord.
If it is the Lord (through Isaiah), then Ahaz (representing the House of David) is being chastised for not asking for a sign. If it is Ahaz, then the House of David is being chastised because they often ask for signs. Nevertheless God gives a sign.
Who is the referent of "And he said" in Isaiah 7:13?