Biddle’s fourth chapter in Missing the Mark is concerned with what lies underneath the previous two themes of the problem of sin: the desire to strive to be more than we are (pride) and the fear to become what we are intended to be (sloth re: Christlikeness). Behind both is what gives life to both of these dimensions:
Basic Mistrust.
Biddle again is on the mark (pun). He surveys how the theme of mistrust ties together a central failure of humans in the whole Bible. He examines Genesis 3, the wanderings of the children of Israel, the prophets, the wisdom literature, Jesus’ teachings, and the theology of John along with Paul’s theme of justification by faith. Deep in this is that “faith” is understood as transcending “believing in” or “believing that” to reach “basic trust.” Biddle’s observations are insightful, and it is not possible to details the evidence.

Finally, Biddle turns to basic mistrust and ministry and I think he shines yet again. He ties together some formative thinkers who find a fundamental location of human problem in basic mistrust (from Kierkegaard to Erik Erikson and James Fowler).
There is a pastoral sensitivity here to something many of us see on a regular basis: if the basic capacity to trust is not developed as persons grow into adulthood, the Christian message to trust God the Father falls flat on ears that don’t recognize the summons for what it is.
So, let me put out how I see Biddle’s basic theory:
Basic sin: basic mistrust of God
Major manifestations: Pride (straining to be more than we are designed to be) and Sloth (fear to become what we are designed to become).
I’m curious if you think this is adequate for defining what the Bible means by sin.