Jewish Mysticism
The four letters YHWA- [the letters YHW] numerically equal 21, and when one considers the pronunciation with an A the sum is 22, corresponding to the twenty-two letters of Torah. This indicates that [with respect to] the one who studies Torah it is as if he mentioned the name (ha-lomed torah ke-’illu mazkir ha-shem).
Translated by Elliot Wolfson in Through a Speculum that Shines- Vision and Imagination in Medieval Jewish Mysticism, Princeton- Princeton University Press, 1994.