Albert Barnes on Luke 24:48

Are witnesses of these things. Of my life, my sufferings, my death, and my resurrection. How solemn was their office--to testify these things to the world, and, in the face of suffering and death, to and proclaim them to all nations! In manner, like all Christians are witnesses for Christ. They are the evidences of his mercy and his love, and they should so live that others may be brought to see and love the Saviour.