brokenness and openness

Once the Baal Shem Tov commanded Rabbi Zev Kitzes to learn the secret meanings behind the blasts of the ram's-horn, because Rabbi Zev was to be his caller on Rosh Ha-Shanah. So Rabbi Zev learned the secret meanings and wrote them down on a slip of paper to look at during the service, and laid the slip of paper in his bosom. When the time came for the blowing of the ram’s-horn, he began to search everywhere for the slip of paper, but it was gone; and he did not know on what meanings to concentrate. He was greatly saddened. Broken-hearted, he wept bitter tears, and called the blasts of the ram's-horn without concentrating on the secret meanings behind them.
Afterward, the Baal Shem Tov said to him: "Lo, in the habitation of the king are to be found many rooms and apartments, and there are different keys for every lock, but the master key of all is the axe, whith which it is possible to open all the locks on all the gates. So it is with the ram's-horn: the secret meanings are the keys; every gate has another meaning, but the master key is the broken heart. When a man truthfully breaks his heart before God, he can enter into all the gates of the apartments of the King above all Kings, the Holy One, blessed be He." (-- Or Yesharim)

Quoted in The master key is the broken heart by the Velveteen Rabbi