Luke 24:46

And he said unto them, Thus it is written that the Christ should suffer, and rise again from the dead the third day; and that repentance and remission of sins should be preached in his name unto all the nations, beginning from Jerusalem.

This is a summary of the great commission which was probably given repeatedly during the forty days prior to the ascension. This announcement of it stressed the importance of the sufferings of the Saviour, and the great corollary of it, his resurrection from the tomb on the third day.

Unto all nations ... is in the same vein of thought as "every creature" in Mark, and "all the nations," as in Matthew. Boles caught the significance of "beginning at Jerusalem" in these words:

They were not to regard even the city where Jesus was crucified as hopelessly wicked and too bad to be benefited by the gospel. The Jewish leaders who crucified Jesus were to hear the gospel and have the opportunity of being saved.[19]

Beginning at Jerusalem ...

Here the reign of Jesus Christ began. Here the dispensation of the Holy Spirit began. Here the reign of Christ upon the throne of David began. Here the reign of the apostles on twelve thrones began. Here the great commission began to be preached. Here the "times of the Gentiles" began. Here the gospel of forgiveness began to be preached. Here the church of Jesus Christ began. Here the evangelization of the world began.