'This Generation' in the Bible

Thou shalt keep them, O LORD, thou shalt preserve them from this generation for ever.

Now also, when I am old and greyheaded, O God, forsake me not, until I have proclaimed thine arm unto this generation, thy might to every one that is to come.

For forty years I was angry with this generation, and said, They are a people whose hearts are turned away from me, for they have no knowledge of my ways;