The meaning of humbleness in English has a slightly different connotation and nuance in Japanese. In Japanese, "unobtrusiveness" may be a more suitable definition.

Many of us as human beings constantly seek recognition from others. One often overhears statements such as "My efforts lead to my success" or "Because I studied hard...". However, the frequent usage of the word "I" (or "my") merely indicates one's ego.
One who distinguishes oneself from others unconsciously limits his ability by setting boundaries around himself, thereby confining himself into a small self-centered world.
However, one who has developed the understanding that although everyone possesses different bodies, each soul is derived originally from the same source, enabling one to make full use of the unlimited resources from this common sub-consciousness world.

Humbleness is one of the most effective triggers which is able to instigate or initiate this power.
"Let's suppose you are given a bowl from the Great Spirit. If that bowl is filled with the selfish thoughts of 'I' or 'my', even though the Great Spirit tries to help, there is no room left in the bowl for spiritual energy to enter. However, on the contrary, if you always think of others, your bowl becomes "empty". The bowl which may seem to be empty, is, in reality full - filled with invisible energy from the Great Spirit filled."

As explained in other chapters, to make one's dream come true is easy if one knows how to use one's sub-consciousness (actually through one's own spirit guide).

Remember, one's ability is very limited if one makes boundaries and distinguishes oneself from others. We should realize that we can live and exist because of other people and many other things through the sub-consciousness world  and through our spirit guides. As you may now realize, usage of "I" or "my" based on self ego does not make sense 

Perhaps the following will help you to understand this concept better.
In your conversations, if you notice yourself stating "My family…", "My money…", "My house…", My car…", etc. -  it should signal a warning regarding the constant usage of these "my" words. The mention of these self-centered terms produces knots on the Silver Cord (described in another chapter), which hinders your spirit guide from helping and guiding you.
According to a higher spirit, "Especially, if you brag about yourself, you should know that you are making a couple of knots on your Silver Cord."

This message discusses humbleness - "Seek good traits in others. Be courageous to admit your shortcomings. Then you will spontaneously become humble gradually." Keep this in mind at all times.