Thawban - may Allah be pleased with him - that the Messenger of Allah (sallallahu 'alaihi wa sallam) said, "Two groups of my Ummah Allah has protected from the hellfire: a group that will conquer India and a group that will be with 'Eessa son of Maryam - 'alaihimas- salat was-salaam." (Ahmad, an-Nisa'i, and at-Tabarani.). This is mentioned in Tarikh Al Firishta, Tarikh AL Baghdadi. Nasrudhin Albani says this is a Sahih Hadith.
Na'im son of Hammad , The teacher of Imam Bukhari in al-Fitan reports that Abu Hurayrah - may Allah be pleased with him - said that the Messenger of Allah (sallallahu 'alaihi wa sallam) mentioned India and said, "A group of you will conquer India, Allah will open for them [India] until they come with its kings chained - Allah having forgiven their sins - when they return back [from India], they will find son of Maryam in Syria."
While Abu Hurayrah said, "The Messenger of Allah (sallallahu 'alaihi wa sallam) promised us the conquest of India. If I was to come across that I will spend my soul and wealth. If I am killed then I am among the best of martyrs. And if I return then I am Abu Hurayrah the freed." (Ahmad, an-Nisa'i, and al-Hakim.)