He who has not the power of alienating is under the necessity of retaining.
Alienation in legal parlance is defined as transfer of ownership of property rights.
Ownership of property rights can be transferred as per the provisions of the Transfer of Property Act, 1882.
Condition restraining alienation are dealt under section 10 of Transfer of Property Act, 1882
In the case of Subhodkumar Vs. Bhagwant Namdeorao Mehetre (2007) 10 SCC 571, the Honorable Supreme Court observed that, A karta has power to alienate for value the joint family property either for necessity or for benefit of the estate. He can alienate with the consent of all the coparceners of the family. When he alienates for legal necessity he alienates an interest which is larger than his undivided interest. When the karta, however, conveys by way of imprudent transaction, the alienation is voidable to the extent of the undivided share of the non-consenting coparcener.