BINT JBEIL, Lebanon - As he pushes a cart full of tomatoes and cucumbers in the market at Bint Jbeil in southern Lebanon, nothing marks out Mahmud as an experienced Hezbollah fighter.
The stocky vegetable vendor in his fifties, who sports a red beard, fought Israel here in 2006, but that battle is now old news.
He has just come back from another front: in Syria, where he fought for 25 days against the rebels who have sought to overthrow President Bashar al-Assad for the past three years.
Since the Shiite movement's chief Hassan Nasrallah gave the order more than a year ago, thousands of Hezbollah fighters have fought in Syria, playing a decisive role in key victories for the regime.
Street vendors, farmers, restaurant owners, medical professionals and students have all joined what they call an "existential battle" against "takfiris" - Sunni extremists.
"When the party called on me to go, I responded. I left my job and I went to stop the takfiris from entering Lebanon," says Mahmud.
"I fought in several regions and took fighters from the region and elsewhere prisoner," he adds.
"Our cause is just. They are mercenaries from Chechnya, Yemen and Libya who want to overthrow Bashar al-Assad, who supported us enormously during the 2006 war against Israel," Mahmud insists.
"It's our duty to help him." Hezbollah has a powerful presence at many levels of society in Lebanon, with representatives in parliament and strong social service networks.
It is backed by Iran, which has long supplied it with weapons through Syria.