Stronger than the "Strong Man"
The context of this statement is Jesus commenting on what leads to a defeated, divided house. The religious leaders criticized Jesus for having a demon and being inauthentic BECAUSE he cast out demons. Jesus responded that it is impossible for a "house" to function when divided against itself. He then gave the illustration recorded in verses 21-22.
Many interpret the "strong man" as a demonic or evil presence. I think that the strong man is the dominant power in one's "house" or life. This may be a positive or negative power.
If the objective is to overcome a house, or person, one must first get past the strong man who protects it. When there is a evil or demonic power "guarding" it, we should overcome that evil power in Jesus' name. On the other hand, if you are the "strong man" guarding your home, don't allow yourself to be bound, leading to defeat and division in your house or life.
Jesus' point was that strong forces can only be overcome by stronger forces.
Overcome in Christ's name when you need to. And don't be overcome when you are called upon to take a stand.