Making yourself of consequence

Princess Dashkova refused to attend these festivities, pleading illness. As the evening progressed, she received a message from her sister saying that the new emperor was annoyed by her absence and did not believe her excuse, and that it might go hard with the princess’s husband, Prince Dashkov, if she did not appear. Dashkova obeyed. When she appeared, Peter approached and said in a low voice, “If, my little friend, you will take my advice, pay a little more attention to us. The time may come when you will have good reason to repent of any negligence shown your sister. Believe me, it is for your interest alone I speak. You have no other way of making yourself of consequence in the world than by seeking her protection.”

Could anyone explain the meaning of the phrase in blue? Thanks!