My dad is 68 and on a fixed income. He's too proud to ask for help but I know money is tight.

Yesterday I went grocery shopping with him. He spent 20 minutes calculating everything in his head, putting items back, choosing generic brands, doing that math my generation doesn't have to do anymore.

At checkout, his card declined. He wasn't even surprised, just quietly asked the cashier to remove items until the total worked.

The woman behind us in line, probably in her 40s, nothing about her screamed wealthy, said ring it all up on mine.

My dad refused. She insisted. He refused harder. She looked him dead in the eye and said sir, someone did this for my family when I was 7 years old. I remember how small it made my dad feel. But I also remember how we ate that week. Let me pass it forward. You can pay me back by doing the same for someone else when you're able.

She paid $83 for his groceries. Refused to give her name. Just said your turn will come and left.

My dad cried in the car. Told me that in 68 years, that was one of the kindest things a stranger ever did for him.

I'm going to remember this. Next time I see someone counting change at checkout, or putting items back, or calculating in their head, I'm going to be that person for them.