Saint Theophan says,
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 go about driving them out? Saint Theophan tells us this is the proper use of our anger.
How can you drive them out? Through inducing wrath that is hostile to them, or by getting angry within yourself against it as quickly as possible.A passion cannot be sustained without your inner support. So when you rise up against it in a strong way it is destroyed and its strength vanishes. The slightest sympathy towards it will sustain it.
Prophet David says in the Psalms,
Be angry, and sin not (Ps 4:5).In other words be angry at the passion and then you will not sin. As soon as you detect even the smallest passion, rise up against it with strength. Realize that this is an attack on your relationship with God. Its action separates you from Him. Use your anger in a constructive way to aid you in coming closer to God.
Reference: The Spiritual Life, pp 233-236