When Kamala Harris was sworn in as vice-president in 2021, she swore her oath of office on two Bibles.

One belonged to our nation’s first black Supreme Court Justice Thurgood Marshall. Marshall inspired a generation, that included Harris, to embrace the law as a means to advancing equality and justice. Harris chose to attend Howard University, Marshall’s alma mater.

The other Bible on which Harris was sworn in was the family Bible of Regina Shelton. Shelton was a neighbour, trusted caretaker, and mentor to Vice-President Harris and her little sister, Maya, as children after school when her mom was working. Harris refers to Shelton as her “second mother”. It was Harris’s actual mother Shyamala Gopalan who guided and encouraged that relationship.

A civil rights activist herself, Gopalan was keenly aware that the world would see and treat her biracial daughters as black women and what that meant in America. She knew it was important for the girls to bond with other black girls and women. Shelton was one of the people who exemplified and passed on to both Harris girls “a responsibility to give and serve”, according to the vice-president.

Vice-President Harris’s dedication to service was not only inspired by her personal relationships. Her chosen path as a lawyer was shaped by important icons who embodied a commitment to freedom, justice, and equity. Justice Marshall was one of them. Another one was Judge Thelton E Henderson.

Before becoming a legendary judge on the US District Court for the Northern California District, Henderson was the first African American lawyer to serve in the Justice Department’s Civil Rights Division. He was a field investigator, working alongside Dr Martin Luther King Jr and other movement leaders. He was famously fired for loaning Dr King his government rental car in Alabama because Dr King’s car had a problem.

Judge Henderson defended the rights of prisoners who were being abused and denied adequate health care. He made the Oakland Police Department more accountable to federal monitoring over police brutality. He was the first judge in the country to recognise the constitution’s guarantee of equal protection and due process rights for gay people — decades before the Supreme Court recognised same-sex couples’ right to marry.

Both Henderson and Vice-President Harris are fierce defenders of civil rights and champions of the law’s role in protecting the vulnerable and marginalised, who understand the importance of laws and regulations that protect our environment and health — and this is no coincidence.

Over our 20-year friendship, I have witnessed first-hand how the powerful lessons from these mentors continue to guide Vice-President Harris in her commitment to justice and service. And I am grateful to all the influences who helped shape and instil that commitment.

Ben Jealous is executive director of the Sierra Club.