Of the two vessels with the same width, the one with the greater depth would be able to hold a larger amount of items. By the same token, depending on the extent to which one humbles himself and empties his heart will determine the magnitude of love with which he can fill himself.
God's love for us was so great that He did not hesitate to give up and send into this world His Only Begotten Son to die on behalf of mankind who had been on the path to eternal death. The reason for different degrees of gratitude from one person to the next lies here. We must realize that the more one humbles himself, the greater amount of God's grace and love with which he can fill his heart. Just as a child could not appreciate the value of hundreds of millions of dollars, God's love can be fathomed only as much as one has felt and experienced it.

"Take My yoke upon you and learn from Me, for I am gentle and humble in heart, and you will find rest for your souls" (Matthew 11:29).
~ from Rev. Dr. Jaerock Lee's column "The Road" carried on the daily newspaper, Hankook Ilbo