Chairman Joint Chiefs of Staff Gen. Martin Dempsey, right, pays respects for three New Zealand soldiers killed in Afghanistan, during a ramp ceremony at Bagram Air Base on August 21, 2012. New Zealand Defence Force via Getty Images Like many users of Twitter, military leaders use hashtags to send out a message, often a motivational one like "#GoNavy" or "#marksmanshipmatters."

However, one former leader's use of a particular hashtag has a more personal message — a reminder of the lives lost in US conflicts and the burden that Gold Star families must bear.

Martin Dempsey, former chairman of the Joint Chiefs of Staff under President Barack Obama and a retired Army general, has on several occasions used the phrase "#MakeItMatter" on Twitter.

During a speech honoring US service members in 2015, Dempsey gave insight to what the phrase means to him and for the families of the soldiers who served under his command during Operation Iraqi Freedom.

"On my desk, less than 100 yards from where we stand, sits a small wooden box," Dempsey said at the time. "And inside that box, there's small laminated cards with a picture of every service member lost in Iraq under my command from 2003 to 2004."

"And on that box are inscribed three simple words, 'Make It Matter.'"

Screenshot via MISSION BBQ/Vimeo

Dempsey commanded the 1st Armored Division during a fierce period of the Iraq War — his box contains 132 cards.

"I carry three of those cards in my pocket at all times," Dempsey continued. "That's all the inspiration I need to try to make my decisions matter, to make their sacrifices matter, to make my life matter. The lives and the sacrifices of those we honor today matter. They matter to me, and they matter to our nation."

Dempsey keeps in touch with the troops' family members on a regular basis.

During a farewell ceremony for Dempsey in 2015, Obama remarked on Dempsey's tradition:

"Those cards were with him a few years back when, for the first time as chairman, Marty spoke to a group of military children who had lost a parent. And that day, as he walked through the crowd — some 600 Gold Star kids, young, so full of hope — he began to think about their lives and how each of them would have to make their way without a father or a mother. And Marty had planned to speak — but he couldn't. So he did one of the things that he does best. He began to sing. And in that moment, the highest-ranking military leader in our nation forged a bond with those children — boys and girls who, at such a tender age, had given up so much — in a way that perhaps nobody else could."

"I've always been fond of the Marine Corps saying 'Semper Fidelis' … Always Faithful," Dempsey said in a speech. "They don't just say it … they live it."

"For Marines, then and now, it's more ethos than slogan," Dempsey added. "So too, the words 'we will never forget' are more than just a slogan."