'Knowest' in the Bible

Give a portion to seven, yea, even unto eight; for thou knowest not what evil shall be upon the earth.

As thou knowest not what is the way of the wind, nor how the bones do grow in the womb of her that is with child; even so thou knowest not the work of God who doeth all.

In the morning sow thy seed, and in the evening withhold not thy hand; for thou knowest not which shall prosper, whether this or that, or whether they both shall be alike good.