How to maintain compassion when dealing with situations?
Xian'er says so: What is compassion?
Wang Xiaowu bullied Xian’er yet again.
Xian’er went to complain to Shifu, asking Shifu to teach him a lesson.

Xian’er thought about it and decided against it.

Shifu will say that we ought to be compassionate and tolerant.
We must have mercy and learn to forgive other.
Feeling helpless, Xian’er hid behind the corner and cried for a while.
Soon after, Xianyi came looking for Xian’er and told him that
Shifu scolded Wang Xiaowu pretty seriously.
Xian’er couldn’t believe it and he was in ecstasies.
But he was confused，so he went to ask Shifu why not so compassionate this time.
Shifu then told Xian’er the secret.
Below are quoted from my Shifu’s new book, Say Good Things—Master Xuecheng’s insight on the path to speaking like a Buddha. 
Compassion is a state of mind, while behaviors are means to an end.
Although compassion may appear as various phenomena, the mind remains the same.
Compassion is to care for the weak and underprivileged as well as to help others in a selfless way. 
Compassion is also to stand up to what is wrong as well as to learn from past mistakes.
What really counts is the state of the mind.
Is it indifferent, contradictory, resentful and contemptuous?
Or is it for the best interest of others? 
Issues in interpersonal relationships are mostly caused by individual afflictions and habits.

One must manage his own afflictions before he is able to help others. Otherwise it does damage to both self and others.

面对境界时如何保持“慈悲心”？
贤二如是说：什么是慈悲
王小五又欺负了贤二。
贤二去找师父诉苦，想给王小五一点教训，
想想又算了，师父肯定又会说，
做人要慈悲、要包容，
要懂得宽恕，懂得原谅别人。
没办法，就自己躲到墙角哭了一会儿。
一会儿，贤一来找贤二，
说王小五被师父给批评了一顿，
贤二开心的不行不行的，但是，还是有困惑，
就去问师父，为什么这次又不慈悲了呢？
师父就向贤二传授了秘法。
以下来自我师父的《好好说话》
慈悲，是自己的心态，外在的行为是方法、手段。
慈悲的外在行相可能有很多种，但心是一样的。
对弱小怜悯照顾、无私帮助是慈悲，
对错误批评斥责、惩前毖后也是慈悲，
最重要的是观照自己的心：
是冷漠的、排斥的、嗔恨的、轻蔑的，
还是希望利益对方的？
人与人之间相处的矛盾，
主要是烦恼习性的碰撞，
必须先调伏自己的烦恼，
才谈得上帮助他人，否则只是自他俱损。