Let us examine the Biblical passage: "And from my flesh I shall behold God" (Job 19:26).
The intention, apparently, is to convey the actuality of a certain perception that is not necessarily sensual, like the certainty of one's self, one's unquestionable sense of existence that cannot really be seen with the eye or touched with the hand.
So, too, is the experience of God a certainty "of the flesh," like the feeling of one's own self beyond the apparent and sensual knowledge of the body.
Although theologians have attempted in vain to explain this philosophically, it is quite apparent to any honest self-observer that the "I" includes the body but is not identical with the body.
The real self is beyond the external, "bigger" than anything one can sense.
When one says "with my flesh shall I behold God," it is an aspect of the Kabbalastic concept of the Divine as filling all worlds–a vision of God intrinsic to the reality of the world.
Whereas when one says, I believe in God, it is of the aspect of the Divine as encompassing all worlds.
–Rabbi Adin Steinsaltz
From "Sanctity and Restraint" in The Candle of God by Rabbi Adin Steinsaltz