DUTIES OF THE WITNESS IN THE SPANISH CIVIL PROCESS
The witness, as a collaborator of the Administration of Justice, is obliged to comply with a series of duties established in the LEC itself (LEC stands for "Ley de Enjuiciamiento Civil" which is basically the Spanish Civil Procedural Law).
Among these duties we will highlight the following ones:
The duty to appear at the courthouse within the term set at the summoning.
The duty to be reachable, being obliged to communicate changes of address.
The duty to take an oath or promise to tell the truth.
Testify (with some exceptions) and the duty to tell the truth, the latter an essential obligation in every witness and whose non-compliance is sanctioned in the Penal Code with the penalties for the crime of perjury.