Derick and Jill Dillard of the new TLC series "Jill and Jessa: Counting On" are so thrilled to celebrate their son Israel David's first birthday this April 6 that they wrote him a heartwarming letter in hopes that when he reads it someday he will have something to remember by.

The Christian couple explained that they named their son Israel because it means "God will Prevail" and "Beloved of God," and it is their fervent hope that he will grow up to become a true follower of Christ.

"Just as the children of Israel are the apple of God's eye, so you are the apple of our eye. A year ago today we held you for the first time and thanked God for giving us you! We pray you will come to know Jesus at an early age and follow him all the days of your life!" they wrote on their blog.

Derick and Jill could not be more proud of the way little Israel is growing up, since they say he is very smart and has a happy disposition. He already knows how to say "mama," "papa," and "nur-nur." The couple explained that Israel says "nur-nur" every time he wants his nurse.

Israel also knows how to do sign language, and every time he makes the signs for "more" or "please," it means he should be given whatever he is asking for.

Derick and Jill shared several other tidbits about their son. They said he loves snacking on fruits such as bananas, papayas, and avocados. He is also fond of the treats his grandmother Cathy Byrum brings him, such as puffs and GoGo Squeeze.

However, one of the best things the couple adore about their son is how happy he is every time they worship God. "You love music and always dance to it when you hear it, or clap with the congregation during worship time in church. You respond with a big smile and raise your hands toward the ceiling when we ask you to say, 'Gloria a Dios,'" they shared.