Sometimes people pay it forward just because they want to spread some joy. Other times, do-gooders are moved by an event in their lives — like when a man treated an entire group of active military members to a meal to honor his recently deceased brother who was a veteran.

On Sunday, one mom in Tennessee was missing her own son so much that she decided to show a little kindness by purchasing breakfast for a family in the car behind her at a McDonald's drive-thru.

Over the weekend, Heidi Goforth posted a sweet note on Facebook that was written on a receipt she received from a stranger. It read: "My son is in the airforce [sic]. I can't buy him breakfast so I bought yours [sic]. Have a blessed day."

"I just had this happen to me. It touched my heart sooo much! I was buying breakfast for my son at McDonald's and the sweet lady in front of me, in the drive-thru, paid for my meal," Goforth wrote in a post along with a picture of the note. "I pray that you see your son soon! He's lucky to have a mom that loves him so much! God bless you and him! Tell him thank you for his service."

The sweet story did not end there.

On Tuesday, two days after paying for a strangers' breakfast, Caryn Scherm Hill, who also lives in Tennessee, learned about Goforth's Facebook post through a news clip that her husband had texted her. Then she went on Facebook, found Goforth's post and left a little note in the comments section.

"Heidi Goforth, it was my pleasure," Hill wrote. "Kindness can create such a wave of emotion. How extra special that you were getting breakfast for your son!!! My son has 17 days remaining in Basic Military Training, testing this week and BEAST WEEK next. I will see him at graduation very soon."

Hill was clearly touched by Goforth's reaction — and the many people who have since commented on her note.

"I cried like a baby when I read the comments from you and others!! Not an hour goes by that we don't think of our son. He is going to laugh when he reads this. We love doing random acts of kindness. It can make so many of us happy. Facebook can really connect," Hill said. "Bless those that protect us and all those that tried! Some didn't make it through basic training but I am so proud they tried. Prayers for those in Med Hold. Heal and get back at it. All in God's time. Heidi you made me smile, laugh, and cry so much in the last 12 hours!!!!"

Goforth told TODAY Food that since receiving Hill's random act of kindness, both moms have been sending messages back and forth on Facebook.

Dozens of other military parents also responded to the post, with many commenting about how it made their day. It just goes to show how far a small act of kindness — especially with a little help from social media — can really go.