'19 Kids and Counting': Anna Duggar and sister talk courtship, marriage before Jessa Duggar's wedding [VIDEO]

Keller sisters Anna Duggar and Priscilla Waller with their husbands, Josh and David during Anna's birthday in Arkansas.Facebook

As her sister-in-law Jessa prepares for her upcoming wedding day with fiancé Ben Seewald, Anna Keller-Duggar shared valuable relationship and marriage advice on a video posted on the Duggar Family Blog with her own sister, Priscilla Keller-Waller.

Anna, who is married to the eldest Duggar son Josh, shared that Priscilla's husband David Waller called Josh exactly three years ago this week. David asked Josh for the phone number of the Keller girls' father to ask for permission to court Priscilla.

Anna also mentioned that Priscilla had to wait for a while before David was able to court her because she was deeply involved in serving the Lord.

Priscilla explained, "Wait for God's best and pray for your future spouse, that he would have a vision for God and a desire to serve the Lord. It was special—when David asked me to breakfast that first morning of our courtship—he bought me 25 roses. Someone counseled me and told me that a wedding day would come and go but to focus on all those other times. That shouldn't be the passion—don't wait for someone to sweep you off of your feet. It's been the best three years of my life."

The Keller sisters also shared several insightful tips for soon-to-be-brides, just like Jessa Duggar.

Priscilla pointed out that brides should never forget about God's presence during the wedding day. She said, "Your wedding day, the most important decision you'll ever make is when you give your life to the Lord and letting Jesus be the captain of your life, letting him be first place and the boss, No. 1, in your life. And the second most important decision is who to marry."

Anna echoed her sister's sentiment, saying "Yes in America we say it is all about the bride and it is her day. But I remember God speaking to me in my heart and saying, 'It's not your day. It's my day.' We need to focus on this is God's day and we need to bring him glory."

Jessa Duggar's wedding date is set on November 1. Catch her, Anna, and the rest of the Duggars in the hit TLC reality show 19 Kids & Counting.

See the video below: