The Archbishop of Canterbury used the christening of Princess Charlotte to warn against "pushy" people ambitious to advance up the ladders of society.
Instead, people wishing for improvement should seek beauty of character, which begins at baptism and is formed through loving and following Jesus Christ.
The Archbishop was preaching to a small congregation at St Mary Magdalene on the Queen's Sandringham estate.
Besides her parents, the Duke and Duchess of Cambridge, the few present included Princess Charlotte's grandparents, Charles, the Prince of Wales, Camilla the Duchess of Cornwall and Michael and Carole Middleton.
The princess's aunt and uncle, Pippa and James Middleton, and her great grandparents, the Queen and The Duke of Edinburgh were also there although not her uncle Prince Harry, currently in Africa for rhino and elephant conservation charities.
The five godparents who made the baptismal promises in the Church of England rite were long-time friends of the couple: Sophie Carter, James Meade, Adam Middleton, the Hon Laura Fellowes and Thomas van Straubenzee.
Archbishop Justin Welby preached a brief homily about love, beauty and Jesus Christ.
Different forms of ambition are wired into everyone, he said.
"In the reading from Matthew 18, Jesus is trying to turn one kind of ambition, an ambition for place and prestige, into an ambition for a beautiful life. To be great in the Kingdom of Heaven, he tells his very pushy disciples, is not about position but about beauty of life, a life that looks like his, and his example is someone unimportant in those days, a child."
He reminded the congregation that among Princess Charlotte's own ancestors, now buried in the Holy Land, is a saint, Russia's Grand Duchess Elisabeth. He said her life was one of "transparent beauty and death one of beautiful courage and service."
St Elisabeth's husband was murdered in 1905 by the Socialist Revolutionary Party. She forgave the murderer and left court to become a nun, founding the Marfo-Mariinsky Convent to serve the poor and deprived of Moscow. In 1918, the Bolsheviks arrested and subsequently executed her. She was canonised by the Russian Orthodox Church Outsie Russia in 1981 and by the Moscow Patriarchate in 1992.
Archbishop Welby said: "In her life she forgave the man who killed her husband. At her cruel murder she continued to care for those suffering with her. It is of such beauty that Jesus speaks when he talks of being great in the Kingdom of Heaven."
He continued: "Such beauty of character begins with baptism, and is established in the habits of following and loving Jesus Christ, habits to be learned from parents and God parents, and the whole community of the church.
"Beauty is the implied prayer of the baptism service, beauty of life which brings true and eternal greatness. In such times as ours, those who suffer, such as the wounded or bereaved in Tunisia and other places, need lives of beauty around them, lives that share healing and hope, offering to all around them, both in times of light and darkness, a vision of a Christ filled future."
The Princess arrived at the ceremony in a traditional perambulator.
The Duchess of Cambridge wore a white Alexander McQueen coat and a Jane Taylor hat as she pushed the pram with the Duke of Cambridge and Prince George, in red shorts and a white shirt with red embroidery, walking beside them.
Princess Charlotte was dressed in a replica of a 172-year-old christening gown first worn by Queen Victoria's oldest daughter in 1841. The replica, made of Honiton lace and white satin, was worn by Prince George for his 2013 baptism and in 2008 by James, Viscount Severn, son of Prince Edward and Sophie, Earl and Countess of Wessex. It was created by Angela Kelly, the Queen's personal assistant and senior dresser, after the original was deemed too delicate for further use.
