In Genesis 6, in the story of Noah, we read "Then God said, 'I will blot out man whom I created from the face of the earth, from man to cattle, and from the creeping things to the birds of heaven, for I am grieved I made them." (Genesis 6:7)

But why would God destroy the creation which His hands have made?  Shouldn't God give them another chance to repent and live?  Where's God's mercy?  This seems too harsh at the first glance.  However, after careful examination, we discover the extent of man's wickedness and understand the amount of grief man caused God.

Earlier in the chapter the Holy Scripture offers the explanation in the following verse "Then the Lord God saw man's wickedness, that it was great in the earth, and every intent of the thoughts within his heart was only evil continually." (Genesis 6:5)  Man's wickedness was great.  It wasn't simple offenses.  But even great offenses could be forgiven if man were to repent.  The scripture however adds that evil was in "every intent of man".  Not just some or most, but man reached a state where every intent of his heart was displeasing to God.  Not only that, but each intent was also "only evil".  It wasn't partially good and partially evil.  It wasn't good towards some and evil towards others.  It wasn't good in certain situations and evil in others.  No, it was only and wholly evil.  But even to this point God would have still been patient with man and draw him to repent.  However, man's evil intent was continuous.  Not just some days it was evil and others it was not.  Not just around certain people of bad influences were man's intent was evil.  It was evil "continually".  Thus the scripture says that man's wickedness was great, every intent was evil, only evil, and continually evil.

The Orthodox Church defines blasphemy against the Holy Spirit as renouncing the work of the Holy Spirit till the last breath.   And since the Holy Spirit is the one Who leads us to repent, our Lord told us that "he who blasphemes against the Holy spirit, it will not be forgiven." (Luke 12:10)  It seems like this was the case here.  This is why the Holy Scripture said earlier in the same chapter "Then the Lord God said, 'My Spirit shall not remain with these people forever, for they are flesh.'" (Genesis 6:3)

However, even here we see God's mercy.  For it took all of mankind to be evil for God to blot out the cattle, the creeping things and the birds of heaven, but it took only one man, Noah, and his family to save all the human race as well as the creation.