Saint Theophan advises us in this way,
No matter how small or weak a passion appears, it is necessary to regard it as if it were the largest and most powerful.How do we respond then to the passions that we seem to regard lightly as we become more spiritually mature? One thing we cannot do is ignore them and surely if we do they will eventually flame up and possibly destroy us.
Saint Theophan says that we have to get very angry at them and treat them with hostility.
Try to stir up anger within yourself against it as quickly as possible. This anger is a firm rejection of the passion. The passionate cannot be sustained unless there is sympathy for it, but any sympathy is destroyed by anger, and the passionate will leave or fall away at the first manifestation of it. Here is the only case where anger is permissible and useful.The Prophet David told us, "Be angry, and sin not (Psalm 4:5).
Saint Paul says, "Be angry and sin not" (Ephesians 4:26).
It s important to always be on the lookout for the work of our passions. It is as if there are terrorists lurking about who want to destroy us. They may be silent and not too visible but we must always be on the lookout and ready to act with quick and firm action against them. Do not delay in action against them when you see even the slightest action of a passion. Your sympathy towards it will only lead to its growth and the potential of a raging fire that you cannot put out.
Saint Theophan says,
Self-indulgence still lives concealed within even long after we have obviously renounced and devoted ourselves to God... Thus, it is necessary to reject this sympathy and stir up anger... As son as you realize a passion's belligerence, get angry at it in a very obvious way.Reference: The Spiritual Life, pp 233-236