Jill Duggar, Derick Dillard, and their baby son Israel David have left the United States to embark on a Christian mission abroad.

Jill's sister Jessa posted a photo of the Dillards, with Jill's and Derick's arms around each other, as they prepared to board their plane. In the caption, Jessa said that she was "so excited" for the couple.

"They've been praying about and working towards this transition since late last year, and are so excited to finally be heading to the mission field!" she said. 

Jessa urged her followers to pray for them and encouraged them to follow the Dillard family blog to get updates about the couple and their mission. 

The couple announced in late June through their personal blog their decision to travel to an undisclosed location for the mission trip. In a blog post dated June 26, Derick revealed that several months previously, a new opportunity arose for them to serve God on the mission field. He said that at first, he had a "huge dilemma" as the provider and protector of his family, but ultimately, they made the decision to go after a friend advised them that "if God was leading us to serve Him abroad, we should pursue it as early as possible to avoid a more difficult move later." 

Derick added that he shared this decision with his manager at Wal-Mart, where he was working at the Tax Department. 

"I recently left the company and we are currently preparing to leave the US and begin our new endeavor in July," he wrote. 

This marks the first time that Derick has addressed reports of him leaving his place of employment which was reported last month, after his brother-in-law Josh Duggar got embroiled in a molestation scandal. 

Following Jessa's post, some of her followers speculated that the Dillards might be going to El Salvador for their mission, while others were adamant that they are heading for Nepal, where Jill and Derick met for the first time. On his July 5 blog post, Derick wrote that they are keeping the specific place of their mission a secret for now for security reasons.  

"For security purposes, at this time, we're not publicly discussing specific times and places of international service," the 26-year old wrote.