Pastor Joel Osteen’s Lakewood Church in Houston is helping Texans cope in the wake of Hurricane Harvey — and trying to counter a flood of comments on social media accusing the church of turning its back on storm victims.

The church took in about 400 people from the overflow at Houston’s George R. Brown Convention Center, a Red Cross shelter, church spokesman Don Iloff said last week.

But to many, it seemed as if the popular televangelist, who preaches a prosperity gospel, could have done more sooner to make the 16,000-seat congregation a haven for those hit by the massive storm, which made landfall on Aug. 25.

Emily Brandwin was one of many on Twitter who took Pastor Osteen to task, tweeting: “When You Know Better, Do Better. Joel Osteen You Knew Better. The city shouldn’t have to ask you to open your Church doors, you knew better.”

Pastor Osteen took to the airwaves to defend himself and his church, explaining last week on national television that contrary to his critics’ claim that the church had remained dry, parts of Lakewood had flooded, and that city officials initially designated the church as a distribution center, not a shelter.

Pastor Osteen, who is widely known for his best-selling books, including “Your Best Life Now,” has a television audience of 7 million for his weekly sermons, and more than 20 million monthly around the world, where he broadcasts to more than 100 countries.

The charismatic non-denominational preacher and his church were widely criticized for not responding in a Christian-like manner to families in Houston affected by the disaster.

Mr. Iloff also disputed the charge that Lakewood had locked out a needy public.

“I can’t repeat it enough: We never closed our doors. We’re a church, for goodness’ sake. In fact, late, late Sunday (evening) or early Monday (Aug. 27 and Aug. 28), we took in three different people who needed shelter,” he continued. “We had staff on site through the storm, and some of those staff were there to take people in if they came.”

Now serving as a shelter, Lakewood has become a receiving station for what Mr. Iloff said “must be at least a ton” of infant supplies and other goods.

He said about 200 people — “most of whom were probably our members” — were on hand to receive donations from lines of vehicles that stretched around the church complex. From Lakewood, volunteers are sending the supplies to the two main Red Cross shelters in Houston.

He said the church property is drying out from waters that nearly breached levees and floodgates around the complex. In 2001, when the church building was the city’s Compaq Center, a basketball arena, it flooded during Tropical Storm Allison.

Lakewood will be responding to Hurricane Harvey “for years to come,” Mr. Iloff added. “We have ministries that go out into the community on an ongoing basis — and have before the storm. But now everything we do is going to be related to this storm. That’s where the need is going to be.”

And while Mr. Iloff admitted it was “surreal” to see Lakewood trending on Twitter thanks to the intense criticism, he said the controversy hasn’t fazed the ministry’s leadership.

“If Twitter can derail your mission, you’ve got the wrong mission,” Mr. Iloff said. “It’s not going to destroy us.”

On Sunday, Sept. 3, which was proclaimed by President Trump as a National Day of Prayer for victims of Hurricane Harvey and for national response and recovery efforts, the service at Pastor Osteen’s megachurch was filled with talk of the deadly storm and its aftermath, and the way forward.

“Harvey came, but it didn’t take us out,” Pastor Osteen said, after congregants listened to a live band accompanied by a light show, while many of the attendees stood and waved their arms. “We are going to come out of this stronger than before.”

Pastor Osteen urged those at the service and those watching online, “Don’t run away from your faith, run to your faith.”

He assured them, “Joy comes in the morning.”