"No bachelors," the guard said.
The newly-renovated park - its boating lake, miniature golf course and neatly manicured lawns - was off-limits to men unaccompanied by women or children, the guard said. "It's for families only."
So-called "bachelor bans" that bar lone men from entering malls and parks on certain days of the week and from living in residential neighborhoods are a common, often loosely-enforced, practice in the conservative Muslim Gulf.
But a recent ramping up of family-only rules in Qatar is excluding the country's vast South Asian workforce, mostly young men who live as temporary residents away from their families, and cutting them off from society, rights groups say.
"I wanted to visit the park but I was turned away," said Hader. "This says to me I am not welcome."
The small Gulf Arab state's reliance on foreign workers to power a $200-billion construction boom ahead of the 2022 World Cup has drawn criticism from labour unions who say migrants are exploited and forced to live in squalid conditions.
A government official said Qatar was seeking to improve conditions for migrant workers.
The tremendous influx of workers has also raised concern among Qataris - outnumbered by foreigners in their own country - that rapid demographic change threatens their way of life.
Qatar's population stands at 2.6 million, 75 percent of whom are male, according to the country's ministry of planning.
No one knows exactly how many Qatari citizens there are as the government refuses to release a total but estimates say there are between 200,000 to 250,000.
"Bachelor workers are eroding the privacy and comfort of families," Rashed Al Fadeh, a Qatari journalist, wrote in a column for local Arabic-language daily al-Sharq last year, saying workers overrunning neighborhoods was damaging Qatar's social fabric.
"Some Qatari families have abandoned habits inherent to them and no longer open their doors to visitors. This hurts us. We are accustomed to being generous towards outsiders ... but now the purity of our lives, sleep and rest is disturbed."
Unsettled by the ferocious pace of development and the strain it has put on resources in his home city of Al Khor, 50 km (31 miles) north of the capital Doha, Nasser al-Mohannadi, a member of Qatar's only elected body the Central Municipal Council, is petitioning the government to introduce family-only days in malls across the country.
"Going shopping without being stared at, enjoying a park not crowded with men who may look at women and not respect traditions. Qatari families have the right to do these simple things," said Mohannadi.
"Today if you go to Al Khor on the weekend you may not see one person wearing traditional dress, no Qataris ... You can feel like a stranger there now."
Authorities have in recent months taken steps to further separate workers from locals: ministry of interior maps which highlight in stark green and yellow Doha's "no-go" housing zones for migrant workers were plastered last month on billboards across the capital.
In December, construction workers were turned away from a parade event along Doha's corniche marking Qatar's national day celebrations.
"Honestly it's embarrassing for all bachelors around Doha," said Sudeep Paraaj, a steel worker from India's Kerala province.
"Friday is a day off for us but if we go to the parks or the big markets we are turned away. It is sad. Doha is limited for us."
Migrant workers who live in labour camps in the desert outside cities often travel to air-conditioned shopping centres in the capital on weekends to transfer money home and escape the summer's searing temperatures.
Other workers use plywood to partition villas in Doha into separate apartments, defying a 2010 law that rules it illegal for workers to live in "family areas".
"Poor housing is part of the problem," said Paraaj. "People in camps who live six to a room want to leave to the city whenever they can."
A government official said relations between local citizens and expatriates were "harmonious" and "deeply respectful" and that Qatar was working to improve facilities for its more than 1.6 million workers including an open-air theatre recently built at a workers' sports complex near Al Khor.
"We are exploring many options including reserving one day a week for workers in public parks when families would not be let in," said the official.
"There is an old graveyard area near Grand Hamad Street [in Doha] which could be developed and set aside for low-income workers for their weekend gatherings."