isaiah 37:30 And this shall be a sign unto thee, Ye shall eat this year such as groweth of itself; and the second year that which springeth of the same: and in the third year sow ye, and reap, and plant vineyards, and eat the fruit thereof. - Free Bible Online

      30. Addressed to Hezekiah.
      sign--a token which, when fulfilled, would assure him of the truth of the whole prophecy as to the enemy's overthrow. The two years, in which they were sustained by the spontaneous growth of the earth, were the two in which Judea had been already ravaged by Sennacherib (Isa 32:10). Thus translate: "Ye did eat (the first year) such as groweth of itself, and in the second year that . . . but in this third year sow ye," &c., for in this year the land shall be delivered from the foe. The fact that Sennacherib moved his camp away immediately after shows that the first two years refer to the past, not to the future [ROSENMULLER]. Others, referring the first two years to the future, get over the difficulty of Sennacherib's speedy departure, by supposing that year to have been the sabbatical year, and the second year the jubilee; no indication of this appears in the context.

JFB.