Hosea 7:9

"Strangers have devoured his strength, and he knoweth it not: yea, gray hairs are here and there upon him, and he knoweth it not."

The tragedy in view here is that Ephraim (or Israel) had permitted the paganism of the old Canaanites with whom they had intermingled to rob them of their relationship to the true God, a pathetic situation compounded and multiplied by the fact that Ephraim was absolutely unaware of what had happened to him.

"Gray hairs ... and he knoweth it not ..." Gray hairs are employed here as a symbol of advanced age, and the senility and weakness that precede death; but even such evident signs as these had been ignored, and he still proceeded as if his strength was unabated.

The twin metaphors of the half-baked cake and the gray hairs were employed for the sake of stressing the vacillation of God's people and the impending approach of their death as a nation.