Do you fear God? There is a test that will determine whether you do or you do not fear God. This test is whether you walk in uprightness or not. To be "upright" means to be one who walks striaght in an ethical sense. It refers to the path that we choose to live in - or how we interact with others. When we walk in an upright manner we are not walking in crookedness. Of course when you speak of uprightness - you are defining this standard and this way of walking by what God says in His Word. We are warned by God in Proverbs chatper 2:13 to stay on the straight path of God's ways, and not to stray into the crooked path which would ignore God's Word and life as we want - or as the world dictates we should. When we do not choose to walk in this way - it indicates that we do not respect God. We don't think that there will be any kind of retribution for our ungodly actions and words. We simple think God does not act according to what His Word says.
The second half of this proverb states things rather bluntly. The one who is devious in his ways despises God. This deviousness simply means that we do not walk in truth. We will try to do things and be deceitful and turn aside from the ways of the Lord. We are crooked and perverse - and according to this word's Hebrew definition we trust in our deviousness to get us through life. Thus we have adopted a lifestyle of doing what we think is necessary to get us what we want. When a man lives like this Scripture says that this man despises the Lord. He holds God in contempt - disdains him - and has no respect for the Lord or for His ways.
It is important for us to get this. To choose deviousness indicates we hate God - and that we have no real respect for what His Word says and how it warns us against God's judgment and discipline. When we choose however to live as God desires - and choose that which is upright and true - that which is by God's design and desire - we are choosing to give God the respect and honor He deserves. A truly wise man does not despise God - He chooses to give God the glory that He deserves.