Rabbi Steinsaltz says:
“There are many forms of Jewish meditation.
Some of them are really esoteric because the systems that supported these ways have not survived to our times.
It is very clear, for example, that the prophets had schools.
There were schools for prophets, and they had their own ways of meditation.
For one thing, their meditation seemed always to be accompanied by music, which is a way that has almost entirely disappeared today, though it still exists in some forms.
In the Chasidic section from which my ancestors come, the rabbi would sing with others for a while and there would then follow a long period of silent meditation.
There were times when my ancestors would do this for six hours; this combination of music and meditation was one way.
But many of the forms really disappeared.
We know, for example, that there were certain postures people took while meditating—in order not to fall asleep as well as for other reasons!
The Hitbodedut type of meditation was developed among the Bratzlaver Chasidim and is an attempt for a personal feeling of communion and conversation with God.
Chabad meditation is entirely different.
This is a form in which one takes a certain idea and thinks about it during a certain time of prayer; sometimes for as long as six or seven hours.
There are still some people who practice this way, silently meditating on a preset problem, a very fine point in Kabbalah or in a book.
The Kotzk meditation is the one perhaps nearest to Zen meditation.
The point of this form is to discard external images, to get rid of empty words, and to reach a point where you are able to say exactly what you mean.
After a very long period of silent meditation, one tries to be absolutely true to the words he says.
It is a terribly tiring process. You find that this or that is not what you mean and so you have to go further on.
And so it goes, on and on for hours until a person has a feeling that he can say something properly.
There is a very famous story about one of the great rabbis who spent his last years in Israel.
He said, “When I was young I used to pray to have the grace to say one prayer properly.
Now I have come to Israel, and it is said that the air of Israel makes one wiser. I now pray to be able to say one word properly.”
There are other mystical forms of meditation that are practiced but not aired very much—and there are many reasons for this.
One of the reasons is that at one time, people were not interested in it seriously and those who did it were terribly concerned about the practice being true and proper.
When it becomes a plaything, when it becomes a fad, there is something wrong about it.
One of the ideas of the sacred is that it is not a plaything.
There is a feeling of distance, and one should not play with it.
And if one cannot, one should perhaps stay out.
This is one of the reasons why for years these forms were not publicized. “
–Rabbi Adin Steinsaltz