Mark 11:26-28 - They arrived again in Jerusalem

11:26

Now many of you may wonder what has happened to verse 26! It depends which translation you have. Some include 11:26, such as NKJV which has 

But if you do not forgive, neither will your Father in heaven forgive your trespasses.”

I.e. It is very similar to Matt 6:15. The earliest manuscripts do not have 11:26, hence its omission.

11:27,28

Jesus and the disciples arrive again in Jerusalem. This is the Wednesday before Passover, and is their third visit. There has been no outright reaction against Jesus’ previous actions (i.e. clearing the temple). However, the religious leaders do come to Jesus and question Him. They ask “By what authority are you doing these things?” and “Who gave you authority to do this?”