What are you crying about, when the sun is shining?

A group of little children were playing. They were running about, picking flowers, singing, and rejoicing, because the grace of God made them happy. Then they saw a monk who was crying.
“Look,” they said to him, “the Lord decorated the heavens with stars and the earth with rivers and gardens; hawks fly high above the clouds and enjoy the beauty of nature; birds sing beautifully in the fields, but you, a monk, sit in your cell and do not see the whole beauty of God. You just sit and cry. What are you crying about in your little cell, when the sun is shining, the world is full of beauty, and there is joy everywhere on earth?”
“Children,” replied the monk, “you do not understand my tears. My soul cries for you because you do not know God, Who created all this beauty. My soul knows Him, and I want all of you to know Him, too. That is why I am sorrowful, and with tears I pray to God for you, that you would also come to know the Lord through the Holy Spirit.”
“What does it mean, to come to know the Lord through the Holy Spirit?” “You cannot know God with your mind. But when you read the Holy Scriptures, where the Holy Spirit dwells, it will delight you, and so you will come to know God and will serve Him with joy day and night. When you know God, the desire to think only about the things of this world will leave you, and your soul will strive to see the glory of God in the heavens.”
- Saint Silouan the Athonite