Isaiah's offer of a sign was one which the prophets of Israel used to make when some crisis demanded the immediate acceptance of their word by men, and men were more than usually hard to convince--a miracle such as the thunder that Samuel called out of a clear sky to impress Israel with God's opinion of their folly in asking for a king;[16] or as the rending of the altar which the man of God brought to pass to convict the sullen Jeroboam;[17] or as the regress of the shadow on the sun-dial, which Isaiah himself gave in assurance of recovery to the sick Hezekiah.[18] Such signs are offered only to weak or prejudiced persons. The most real faith, as Isaiah himself tells us, is unforced, the purest natures those which need no signs and wonders. But there are certain crises at which faith must be immediately forced, and Ahaz stood now at such a crisis; and there are certain characters who, unable to read a writ from the court of conscience and reason, must be served with one from a court--even though it be inferior--whose language they understand; and Ahaz was such a character. Isaiah knew his man, and prepared a pretty dilemma for him. By offering him whatever sign he chose to ask, Isaiah knew that the king would be committed before his own honour and the public conscience to refrain from calling in the Assyrians, and so Judah would be saved; or if the king refused the sign, the refusal would unmask him. Ahaz refused, and at once Isaiah denounced him and all his house. They were mere shufflers, playing fast and loose with God as well as men. _Hear ye now, O house of David. Is it a small thing for you to weary men, that ye must weary my God also?_ You have evaded God; therefore God Himself will take you in hand: _the Lord Himself shall give you a sign_. [16] 1 Sam. xii. 17. [17] 1 Kings xiii. 3. [18] Chap. xxxviii. In order to follow intelligently the rest of Isaiah's address, we must clearly understand how the sign which he now promises differs in nature from the sign he had implored Ahaz to select, of whatever sort he may have expected that selection to be. The king's determination to call in Assyria has come between. Therefore, while the sign Isaiah first offered upon the spot was intended for an immediate pledge that God would establish Ahaz, if only he did not appeal to the foreigner, the sign Isaiah now offers shall come as a future proof of how criminal and disastrous the appeal to the foreigner has been. The first sign would have been an earnest of salvation; the second is to be an exposure of the fatal evil of Ahaz's choice. The first would have given some assurance of the swift overthrow of Ephraim and Syria; the second shall be some painful illustration of the fact that not only Syria and Ephraim, but Judah herself, shall be overwhelmed by the advance of the northern power. This second sign is one, therefore, which only time can bring round. Isaiah identifies it with a life not yet born.