SHEIKH 'ABDULLAH 'AZZAM (ASY-SYAHID, INSYAALLAH)
"...Allah's way of building the human soul is to develop it gradually, just like a building. You build a building floor by floor, placing one brick over the other, etc. until the human soul is fully built.
The human soul cannot be built overnight, it cannot be built overnight. It needs a long time to be built...build it gradually, just like the body grows gradually. When a person is born, he is half a meter tall, for example. One day, he will be seven years old, and one day he will be seventy-five years old. He will grow from being a meter tall to being a meter and a quarter tall, etc. When he gets to be twenty years old, he will be between 170 to 175 centimeters tall.
The human soul is exactly like this when it comes to gradually growing in the religion. This is why the Lord of Honor would reveal the Qur'an one, two, or three verses at a time and would require them to act upon those verses. The Companions of the Messenger of Allah would take one, two, or three verses - never more than ten at a time - and then go act on them. They would then come back, learn some more, and go act on what they learned. As Ibn Mas'ud said: "We learned knowledge and action with the Qur'an."
Therefore, it is very dangerous for you to have a lot of knowledge while having only a modest level of action. The one who hears you thinks to himself 'Ma Sha' Allah!' He hears you talking about this verse from the Qur'an, this hadith, the hadith being authentic, the hadith being weak, 'Aqidah, Islamic history, the Khulafa', 'Umar said this, Abu Bakr said that - may Allah be Pleased with them all.
However, you are ten centimeters when it comes to action, and when it comes to knowledge, you are over three meters. There is no balance! This is a disease. Having a lot of knowledge without action is a disease just like having a lot of action without knowledge.
There is a disease in the medical field known as hydrocephalus. It is when someone's head becomes so enlarged that his body is unable to carry it. I saw someone with his head like this, his body was thin, and his knees were unable to support his head. It could not! This is what many people look like: they learn a lot of knowledge - they memorize, they do not learn - they memorize. However, his head is poised like this while his body and limbs cannot support it. The size of a person's head must be consistent with the size of his body. Otherwise, he will be considered diseased if any part of his body grows larger while the rest of his body doesn't grow. If the medicine he takes all goes to one part of his body - for example, it all goes to his nose - his nose will become bigger than the rest of his head, and he will be deformed!
So, the Religion of Allah is a gradual divine method of developing the human soul just like this. Just like a medicine dropper administers the medicine gradually, they would take two verses or two ahadith, and they would go act upon them just like this..."
['at-Tarbiyah al-Jihadiyyah wal-Bina''; 3/182-183]
(SHEIKH 'ABDULLAH YUSUF 'AZZAM (ASY-SYAHID, INSYAALLAH)