Can the Angels sin? No, it is impossible for them to sin, because they behold the face of God. They continually contemplate His infinite goodness, and derive thence a perfect happiness which satisfies every portion of their nature. Outside God there is nothing which has any attraction for them. There is no good possible for them except in doing His will; hence they cannot sin. Whenever I sin it is because I grasp at some temporal good instead of God, and this though I know in the end it will bring me misery.

Are the Angels free if they cannot sin? Yes, perfectly free. He who freely chooses evil instead of good abuses his freedom. He does his best to make himself a slave instead of free. Perfect freedom is the freedom of those who choose only out of various ends all leading to God. God is the end at which the angels always aim, but they are free to choose the means which lead to that end. We do not always choose God, but our own pleasure, as the end at which we aim. Hence we are always impairing our freedom. How can we choose right means when our end is not rightly chosen?

Hence the Angels are far more free than we are in their choice. They always choose means which lead to God. We get in a state of confusion because our intention is not pure. We seek self, not God; this hampers us and ties us down. We are conscious of something that hinders our liberty; this is nothing but self-will preventing us from always seeking God.