What does Zhang mean by this passage? Please translate and explain, thank you.

If you just want to understand the meaning, it is not difficult to understand. If you need to study the meaning of some words, you should be careful.

I understand:

The so-called benevolence, but the heart is fair. The truth of being a man is a long story. If you do a good job and have a result, even if it is a natural thing, you can't expect it in your mind. If you have expectations in your heart, you will become selfish. Now we can only do something that is closely related to life before it becomes very difficult. As for the effect after completion, just wait for the result to come out. You can't calculate and compare in your mind, but you can only expect a certain result to come. In this way, by adhering to the principle in our hearts, we can simply maintain a fair and just mind, regardless of utilitarian thoughts. Can't it be called "benevolence"?