In Re berubari Union case the Supreme Court has said that Preamble to the constitution is a key to open the mind of the makers and shows the general purpose for which they made the several provisions in the constitution. In the same case the Supreme Court has also held that Preamble was not a part of the constitution and therefore it could never be regarded as a source of any substantive powers, it has limited application and can be restored to where there is any ambiguity in the statue.
But in the case of Keshavananda Bharati Vs State of Kerala A.I.R. 1973 SC 1461 The Supreme Court rejected the view expressed in the berubari case and held that Preamble is a part of the constitution. In ordinary statute not much importance is attached to the Preamble, all importance has be attached to the Preamble in a constitutional statute.