Jamieson, Fausset and Brown on Mark 13:9

9. But take heed to yourselves: for--"before all these things" (Lu 21:12); that is, before these public calamities come.

they shall deliver you up to councils; and in the synagogues ye shall be beaten--These refer to ecclesiastical proceedings against them.

and ye shall be brought before rulers and kings--before civil tribunals next.

for my sake, for a testimony against them--rather "unto them"--to give you an opportunity of bearing testimony to Me before them. In the Acts of the Apostles we have the best commentary on this announcement. (Compare Mt 10:17, 18).