Following her graduating, Sampson immediately went into the active Anglican sisterhood of
Society of Saint Margaret in East Grinstead, On 14 September 1932, she was professed as Sister Margaret Clare. Sampson was an educator at the school and resided at the society's school in
Cardiff when
The Blitz was occurring. that was based in Oxford after she earned a successful transfer. Sampson was received as Sister Mary Clare of the Precious Blood on 6 August 1943. She was elected as Mother Superior of the Community of the Sisters of the Love of God on 3 April 1954. Supported by the
Community of St John the Evangelist and working closely with their warden
Gilbert Shaw, Sampson began working for life for the Community of the Sisters of the Love of God. Her work was heavily influenced by Shaw; Kenneth Leech of
The Independent wrote that the two assisted in the forming of an "understanding and practice of contemplative living in the midst of a world of action." Under Sampson's leadership, she oversaw the opening of the new foundation in Bede House close to
Staplehurst,
Kent in 1967. Sampson established the SLG Press that published literature concerned with Christian spirituality such as its Fairacres Pamphlets to a wider audience. This was done in response to the growing eagerness of Christians and non-Christians to learn about Christian mystical tradition. Sampson encouraged and took part in ecumenical dialogue, particularly with the Roman Catholic and Orthodox churches, and helped other religious communities seek ways to achieve reconstruction. Church leaders consulted her and she partook in important meetings and conferences. In 1973, Sampson returned as Mother Superior. Eight years later, she published the book
Encountering the Depths about her spiritual teachings. Sampson's written records have remained largely unpublished. In it, she stated four needs for contemporary churches: living with eternity, the gift of knowing and interpreting God's actions "in the present crisis of the world", committing to the healing and wholeness of humans and their communities, and recognising the role of the praying community "as the spearhead of the conflict with the powers of darkness." ==Death==