The ocean is vast and boundless. But the amount of water you can carry from it is determined by the size of the vessel you take. If the vessel you carry is small, you cannot fill it beyond its capacity. Likewise, if your heart is constricted, Divine grace will be equally limited. Broaden your heart and receive the plenitude of God's grace.
How is one to broaden his heart? It is by getting rid of narrow differences and by curbing desires. By developing insatiable desires, the heart gets shrunk. A broad heart means recognizing the truth that the Divine dwells in everybody. Only then can you obtain the Reality that is unchanging and eternal.
(SSS Vol XXIII - Chap 4)