These 4 parshiyos resemble our journey in recovery.
First comes Shkalim, which means we have to weigh our actions, put them in balance - the inventory.
After that comes Zachor: we find the bad that has to be eliminated and we do so just like with Amalek.
After we got rid of the bad, comes Para - the red heifer - that brings Tahara because we got rid of the bad.
And this is when we reach Hachodesh in which we are new - Hischadshus - we are no longer what we used to be but we have recreated ourselves. Amen, so it will be.