A collection of Albert Einstein's letters are due to be auctioned in June, including some which detail his views on God.

One letter written to 'Mr Guy H Raner Jr' and dated July 1945 says: "From the viewpoint of a Jesuit priest I am, of course, and have always been an atheist... It is always misleading to use anthropomorphical concepts in dealing with these outside of the human sphere – childish analogies.

"We have to admire in humility the beautiful harmony of the structure of the world – as far as we can grasp it. And that is all."

However, though he rejected the idea of a personal God – referring to it as "childlike" – Einstein also distanced himself from "the crusading spirit of the professional atheist whose fervor is mostly due to a painful act of liberation from the fetters of religious indoctrination received in youth."

"I prefer an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being," he wrote in a second letter, sent in September 1949.

The collection of 27 documents is one of the largest of Einstein's to be offered at auction. Other letters in the collection discuss Fried, Nazi Germany, Einstein's theory of special relativity and the atomic bomb. CEO and President of Profiles in History, Joseph Maddalena, told the Daily Mail that it is "the most important grouping of Einstein writings to ever be sold."

"These letters depict his innermost views, offering intriguing content as only Einstein can, this collection is an embodiment of the physicist life's work," Maddelena added. "We are in uncharted territory, this is going to draw out a lot of collectors."

The collection could procure up to $1million in total, but it's not the first time that Einstein's writings have fetched a large sum. A single letter sold for £49,000 at auction earlier this year, and in 2012, the physicist's 'God letter', in which he established his disbelief in a biblical God, was bought for more than $3 million.