B1 He Himself is
B2 The propitiation
C1 For our sins
C2 Not only ours
C3 Of the whole world
C1 God is angry
D1 He has warned us.
D2 He will punish.
D3 He has provided a way for forgiveness and reconciliation.
D2 Sin has to be punished.
D3 Jesus, the sinless Advocate, has paid, suffered, for our sins.
D4 God is willing to accept this propitiation for our sins if we meet His conditions.
D5 His conditions are confessing and asking forgiveness. He also requires repentance and the proof of repentance.
E1 Confession is admitting our sins.
E2 Asking for forgiveness.
E3 Repentance is a turning away from this/these sin/s.
E4 Proof of repentance is our making things right and also not doing the sin again.
F1 If we steal, then we will not steal anymore and will pay what we owe.
F2 If we lie, then we will not lie anymore and will go to those to whom we lied and tell them the truth.
D6 And the tax collector, standing far away, would not so much as lift his eyes towards heaven, but beat on his chest, saying, 'God, be merciful to me a sinner!' (Luke 18:13, EMTV). Be merciful is a related word to propitiation.
B2 Extent of the propitiation
C1 Our sins
C2 The whole world's sins
C3 See here for an article on the extent of the atonement.
B1 Why did Jesus volunteer to be the propitiation?
B2 Why can't we take care of our sins ourselves?
B3 Why didn't He did for only our sins?
B4 Who is the "whole world?"