From Sahih Muslim (Hadith 4826):
It has been reported on the authority of Mujashi' b. Mas'ud as-Sulami who said:I came to the Prophet (ﷺ) to offer him my pledge of migration. He said: The period of migration has expired (and those who wereto get the reward for this great act of devotion have got it). You may now give your pledge to serve the cause of Islam, to strive in the way of Allah and to follow the path of virtue
Reference: Muslim 4826