A son of God who only sees himself as a sinner fails to recognize the fullness of what Christ accomplished for us on the cross. By giving us a new nature He gave us a new identity. If I am saved from sin and washed clean in His blood but still define myself by sin by calling myself a present tense sinner, I’m contradicting the victory of the cross.
For the child of God who recognizes the free gift of righteousness granted to him in Christ yet never stops to thank God for saving him his sins and from being a sinner fails to humbly acknowledge where he has come from.
When we fail to remember what the grace of God saved us from we are in a dangerous place.