Regarding the verse from The Method to Transform a Suffering Life into Happiness (Including Enlightenment) [see p.13]:  

As I have already given this body, an impure aggregate,
To all beings to use for their pleasure,
Even if they kill me, criticize me, beat me and so forth,
I will let them do whatever they like.

Here you have to know the whole point is to dedicate from your side totally to sentient beings, like water, earth, fire, wind, and like the sky, as it is said in the Bodhicaryavatara [A Guide to the Bodhisattva's Way of Life]. This is what to practice, to become enlightened, as well as tonglen or the bodhisattva attitude. But remember bodhicitta is secret, for the lower intelligent bodhisattvas.

Of course for beginners, there’s no question that they can’t practice this immediately, they can’t accept it immediately. Even if it is explained, it takes time. Some people who don’t have much merit have to wait for a long time, and for them it’s not possible to practice this brave heart, bodhicitta, in this life. In order to do this we need unbelievable merits, like fuel or oil for a plane to fly. Those who can practice this are unbelievably lucky, most unbelievably lucky, to be able to practice bodhicitta.

You have to know that Western life, in particular, is dedicated to developing the selfish mind. Of course, that is the door to suffering, that is the enemy of the root of full enlightenment, bodhicitta. If there is no bodhicitta, there is no enlightenment for sentient beings. Then you will be in samsara and experience the oceans of suffering again and again, the endless sufferings of samsara. 

For ordinary beings, the main thing is to dedicate and to serve others. That is what we need to be habituated in, and that is totally against the self-cherishing thought, the great demon of ours.

The ant or mosquito or anyone who created the negative karma to be born in the lower realms numberless times, the karma did not get purified before, so then they are reborn as an ant or mosquito and so forth. No matter how much suffering, if it is materialized, then it is like the sky, the karma ripened already.

We have been born as a human being many times before, and we have been born as a mosquito and an ant numberless times and have had to suffer numberless times. [We need] to understand karma and to have compassion to them, and see this as a reminder of how important it is to practice holy Dharma, to purify.

When we experience harm from others we have to accept it and feel happy. Like Geshe Lama Konchog, when he fell, his first thought was that he was so happy because he received my life obstacle on him.

That is what should happen, to be so happy that the other sentient being got what they wanted.