H. Further explanation of the way of meditating

1. The details of meditation after this is familiar,

Now the way of meditating will be further explained. As it says above:

After this is familiar, then, beginning with kindness,
Meditate on all four, one right after the next,
With a gradual break in attachment to any of the four.

Sometimes meditate on these four in order, as an antidote to liberate them into purity.

2. How to stop obstacles to kindness with compassion

Moreover,

If meditation on kindness attaches you to all beings
Making you feel as if they were your relatives,
By compassion stop the cause and effect of the pain, attachment.

If sometimes you become permanently attached to other sentient beings as your father and mother, a second meditation on compassion will serve as an antidote.

3. How to stop obstacles to compassion with joy

Moreover,

When a lesser compassion attaches to reference points,
Sadness will be stopped by a joy that has no object.

When there is attachment to compassion for an individually characterized phenomenon, illusion-like, objectless joy will clear away all sadness and attachment.

4. How to stop obstacles to joy with equanimity

Moreover,

When joy disturbs the mind by arousing anxiety
Then we should meditate on the great equanimity,
Free from all desire for anything near or far.

If we are sad because we long for joy in the happiness of others, it will be cleared away by meditating on objectless equanimity.

5. Stopping the obstacles to equanimity with kindness

Moreover,

When equanimity is neutral and indecisive,
Meditate on kindness and so forth, as before.
Training, in that way, grows to be easy and stable.

If everything seems to become indifferent, arouse kindness and meditate on that.

These are the general antidotes. In particular, as an antidote for each object, meditate as taught in the corresponding objectless way. By meditating in that way, we will attain immeasurable peace within ourselves and quickly attain stability.

6. The way of meditating when we have become increasingly familiar

Yogins for whom this practice is fully stabilized
May meditate in a different order, or jump about.

After the four immeasurables are stabilized, so that their benefits may arise, after kindness, meditate on the others in order, or after equanimity go back and meditate in no particular order.  That is, after meditating serially on kindness, compassion, joy, and equanimity, after equanimity, meditating on compassion and kindness is the lesser degree. After kindness, meditating on joy is the middle. After equanimity meditating on kindness is the greatest. Jumping directly up and down after resting between objects is the meditation. The Middle Length Prajñaparamita says:

Subhuti, then meditate on kindness. Meditate on joy. Rest in compassion, Practice equanimity.

7. The virtues of meditating in this way

What is the purpose? It is like this:

By that our realization will gain the advantage of freshness.
Its steadiness will grow to the very greatest degree.

In particular the mind of the four immeasurables will gain freshness, unsteadiness will be steadied, and steadiness will become supremely great steadiness.