The Duggar siblings grew up very close to one another, and they try to share each other's milestones with one another.

When Jessa Seewald gave birth to her first son Spurgeon Elliot this November, she admitted that she was heartbroken that her elder sister Jill Dillard was not around to witness it.

Jill and her husband Derick were in Central America serving in their new ministry during the time of Jessa's labour. In the TLC documentary "Jill and Jessa: Counting On," Jessa shared what went through her mind during her pregnancy knowing that Jill would not be a part of her son's birth.

"It's really sad to see Jill and Derick go," the 23-year-old mother said. "We're super close as sisters. And kind of selfishly, I'm like, 'I really want you to be here when I have a baby. You could be so much help and everything. That's probably the most tough part about it for me."

Of course, Jill knew how difficult it was for her sister to be away from her, so she wrote Jessa a heartfelt letter detailing the joys and challenges she can expect as a mother.

"I can't believe you have a little one now! It was such a joy to get to be a part of the birth from Central America, thank you. You were a champ! I felt those contractions with you," Jill wrote.

Jill reminded her sister that if they abide by the teachings of Jesus Christ daily, God will help them be the wives and mothers He wants them to be. "God's grace is sufficient in our weaknesses (we definitely aren't perfect)!" she said.

"I'm so excited to both be on this motherhood journey together! I pray our boys will love Jesus with their heart, soul, mind and strength and love others more than themselves!" she said.