See - philja.judiciary.gov.ph/alerts/2013/fax_march2013.pdf
"x x x.
Judge: conduct unbecoming of a judge -
Section 35 of Rule 138 of the Rules of Court expressly prohibits sitting judges from engaging in the private practice of law or giving professional advice to clients, and Rule 5.07 of the Code of Judicial Conduct reiterates the prohibition.
The prohibition is based on sound reasons of public policy considering that the rights, duties, privileges and functions of the office of an attorney are inherently incompatible with the high official functions, duties, powers, discretion, and privileges of a sitting judge. It also aims to ensure that judges give their full time and attention to their judicial duties, prevent them from extending favors to their own private interests, and assure the public of their impartiality in the performance of their functions.
Respondent judge violated said rules on prohibition when he assisted his daughter (who was the lawyer of his wife) at his wife’s administrative case by coaching his daughter in making manifestation and preparing questions for her daughter.
For conduct unbecoming of a judge, respondent was fined P40,000.00 (A.M. No. RTJ-10-2217, April 8, 2013).
x x x."