Why the tradition of Guru Dakshina

Expressing gratitude for the knowledge received from the Guru is called 'Guru Dakshina'. By giving Guru Dakshina, the disciple demonstrates his ability, authenticity, and devotion. By doing so, the disciple frees himself from the burden of accepting donations, but he is not free from the Guru's debt for life. Guru Dakshina has no conditions. That is, Guru Dakshina is a matter of the disciple's ability and faith. Sanskrit literature contains many unique examples of Guru Dakshina, which reveal the dignity of this supernatural relationship. Guru Dronacharya asked Ekalavya for his thumb as Guru Dakshina, and Ekalavya readily gave it. While interpreting this incident, people forget that Dronacharya could have asked for his entire hand instead of his thumb. Ekalavya would have given that too. Guru Dronacharya also suggested to Ekalavya how to use his thumb to shoot a bow.  The difference between a worldly guru, i.e., Acharya, and a spiritual guru should always be kept in mind when discussing or analyzing these relationships.