The pastor of New York's Redeemer Presbyterian Church has been married for 37 years and has been led to discuss his thoughts about how God designed the sacred institution.

Talking about their book, The Meaning of Marriage: Facing the Complexities of Commitment with the Wisdom of God, Tim and Kathy Keller talked about their experience.

 Tim Keller: Popular Belief About Marriage Is Wrong

Love, marriage and sex the way God designed were the topics during a seminar hosted by a marriage advocacy campaign and streamed live over the Internet Tuesday and at the website operated by Redeemer Presbyterian Church.

"Let’s Strengthen Marriage," a national campaign, also gave the Kellers a chance to discuss their new book. The book was released on Tuesday as well.

Keller and his wife stressed the importance of establishing and maintaining a friendship throughout all phases of a relationship, including when dating as singles.

The determining factor when deciding whether to marry someone should be whether both people in the relationship want to help each other become what God has planned for them individually and together, said the couple.

"To fall in love truly is to fall in love, not only with the person as they are, but also with the person you know that God is making — that God is turning them into," Keller said. "In other words, you get glimpses of future greatness [even though] you know the person is very flawed. Yet, you get excited about their future self as well as who they are now and you say 'I want to be a part of getting you there.' "

Keller, who leads Redeemer Presbyterian Church in New York City, said the desire to see the other person succeed in Christ should be mutual.