'Sign' in the Bible

‘Then this shall be the sign for you: you will eat this year what grows of itself, in the second year what springs from the same, and in the third year sow, reap, plant vineyards, and eat their fruit.

Now Hezekiah said to Isaiah, “What will be the sign that the Lord will heal me, and that I shall go up to the house of the Lord the third day?”

Isaiah said, “This shall be the sign to you from the Lord, that the Lord will do the thing that He has spoken: shall the shadow go forward ten steps or go back ten steps?”