The fact that we do not fully comprehend the bond does not mean that we know nothing about the bonds. On the contrary, we know a lot; we have a firm theoretical basis of their existence and nature based on a plethora of experimental and computational studies. For example, we know that the bond mostly is a subtle equilibrium between electrons-nuclei attractions, nuclei-nuclei and e --e - repulsions, and kinetic contributions that reach a minimum in the potential energy surface. However, the point is that:  We certainly do not know everything. There is still much to learn.