Al-Imam Ahmad, may Allah have mercy upon him, was asked about a man who stays in his country and therefore descends one level in Hadeeth (extends his chain of narration in Hadeeth by one one man ). He said:
"It is not like this that knowledge is sought, if knowledge was sought in this manner, knowledge would die. Indeed knowledge is taken from the Akaabir (major scholars). "
If only going down one level in Hadeeth is a cause for the death of knowledge, then what type of knowledge do those who belittle and insult the major scholars have?
 The man could have traveled and taken the Hadeeth from a major scholar of Hadeeth, however, he stayed in his country and took the Hadeeth from one of the major scholar's students, therefore his Hadeeth now has one extra individual in the chain, this is known as 'descending' in the level of Hadeeth. Likewise minimizing the number of narrators in a chain of narration 'ascends' the level of the Hadeeth.