Humility means getting your ego out of the way, so that you can connect with God or Source energy. As identification with ego implies separation from God or Source, I believe humility is necessary to progress spiritually.
Humility doesn't mean having low self-confidence. To the contrary, many humble people are supremely self-confident because they are naturally connected to Source energy. But they don't boast about that confidence, because they don't have to prove to others that they are worthy. Rather, they are grateful and appreciative of the abundance that comes from being connected to Source energy, and willing to share that abundance with others.
In Buddhism, humility is equivalent to a concern of how to be liberated from the sufferings of life and the vexations of the human mind. The ultimate aim is to achieve a state of enlightenment through meditation and other spiritual practices. Humility can also result from achieving the liberation of Nirvana. When one experiences the ultimate Emptiness and non-self, one is free from suffering, vexations, and all illusions of self-deception. Humility, compassion, and wisdom characterize this state of enlightenment.