It is the duty of a householder to receive guests or atithis, even if a guest be an enemy. The word atithi refers to one who comes without an invitation. When a guest comes to one’s home, one should properly receive him by standing up and offering him a seat. It is enjoined, grhe satrum api praptam visvastam akutobhayam: if even an enemy comes to one’s home, one should receive him in such a way that the guest will forget that his host is an enemy. According to one’s position, one should properly receive anyone who comes to one’s home. At least a seat and a glass of water should be offered, so that the guest will not be displeased.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Eighth Canto, Chapter 16 – Text 6