Jansenism

Jansenism belongs to a family of perfectionist teachings that occur regularly throughout Church history: Pharisaism, Pelagianism, Puritanism, probabilism, legalism, quietism, rigorism, rubricism, "super-spirituality," etc. It is easy to persuade good Christians that they must be "perfect as the Father is perfect" (Mt 5:48).

For St. Ignatius, these are "temptations of the Second Week." Cf. Choosing the right good.

Perfectionism breeds depression. "It doesn't have to be perfect to be good."

Five Jansenist teachings condemned by the Pope:

The condemned teaching	The true teaching
There are some commands of God which just men cannot keep, no matter how hard they wish and strive.	God gives us the grace we need to obey Him.
It is impossible for fallen man to resist sovereign grace.	God is the author and the guarantor of human freedom; he gives us the power to say no to Him.
It is possible for human beings who lack free will to merit.	It is our free choices that make us Christ-like and enable to share in His glory.
The Semipelagians were correct to teach that prevenient grace was necessary for all interior acts, including for faith, but were incorrect to teach that fallen man is free to accept or resist prevenient grace.	We cannot keep God from offering us salvation but, no matter how strong the offer, we choose to say yes or no to God.
It is Semipelagian to say that Christ died for all.	God's love for us is not measured out nor caused in any way by our awareness of needing Him. Jesus died for all of God's children because God loves all of His children.