The law protects us to a certain degree in this fallen world.  If you do not kill or steal you will not go to prison for being a murderer or a thief. 

Do we obey to gain God's blessings?  Or because we love God?  God says, "If you love me you will keep my commandments."  Keeping God's law means we are to love each other and love God. That is what we owe God--our love.  Obedience is a sacrifice of worship and praise.  Trusting Christ brings peace and joy to the believer.  But because you do the right thing it does not mean your life will be plentiful financially, in ministry, relationships or physically.  As a matter of fact the Christian is promised suffering.  Our hearts are to follow Christ out of deep gratitude and trust. 

If you say I will disobey just because I am forgiven, then you don't understand grace.  You are in rebellion towards God.  To willfully sin is as if you crucify Christ again.  God says He trains those He loves.He will pull the rug out from under you.  If you are His, He will come get you and drag you home. Look at Jonah.

Scripture says God blesses the just and the unjust.  I believe it gives God great joy to bless.  He even uses our sin to bless us.  He does not bless us nor love us because we are good.  We may suffer consequences of bad choices.  No doubt we will unless God intervenes.  God blesses to bring Himself glory.  So that we will know Him and His character.  God is good.  He uses blessing to win spiritual battles for us.  To bring awe to Himself from the heavenly host.   It brings God great pleasure to bless His children.  Can you relate to that?  But who can know the mind of God?  I just know  that I have received blessing after undeserved blessing.