In a moving Instagram post, Michelle Obama reflected on the loss of her mother, Marian Robinson, who died last Friday, May 31, at the age of 86.

The former first lady and her family eulogized Robinson and the vibrant life she led in a statement, received first by NBC News and later posted on Michelle and Barack Obama’s Instagram pages.

Accompanying the statement on Instagram was Michelle Obama’s touching caption, calling her mom her “rock.”

“My mom Marian Robinson was my rock, always there for whatever I needed,” the former first lady wrote.

“She was the same steady backstop for our entire family, and we are heartbroken to share she passed away today.”

The former first lady went on to express her desire to “offer some reflections on her remarkable life” in a tribute that detailed her mother’s early life and her marriage to Michelle Obama’s father, Fraser C. Robinson III, who died in 1991. The statement was signed by Michelle Obama, her brother, Craig Robinson, and other members of their family. It touched on Robinson’s role as a grandmother to her grandchildren — including Malia and Sacha — and mother-in-law to former President Barack Obama.

“On Election Night in 2008, when the news broke that Barack would soon shoulder the weight of the world, she was there holding his hand. With a healthy nudge, she agreed to move to the White House with Michelle and Barack. We needed her. The girls needed her, and she ended up being our rock through it all,” the family statement reads in part.