This verse deals with becoming aware of delusions, recognizing them as faults and abandoning them as soon as they arise.
Shantideva said that if we look at the reason we don’t get beyond our current situation, we’ll see it is our mental delusions.
Take anger, for example, one of the worst delusions. With awareness you can learn to recognize this delusion as soon as it arises and ask yourself what it is doing to you. By realizing that it is not producing anything useful, you will not want to be involved with it and when you are not involved, it ceases to be anger.