Albert Barnes on John 15:21

My name's sake. On my account. Because you are my followers and possess my spirit. Jn 14:13.

Because they know not him that sent me. They will not believe that God has sent me. They do not so understand his character, his justice, or his law, as to see that it was fit that he should send his Son to die. They are so opposed to it, so filled with pride and opposition to a plan of salvation that is so humbling to men, as to be resolved not to believe it, and thus they persecute me, and will also you.

(y) "But all these things" Mt 10:22, 24:9