Many cover their eyes with their right hand during the first line of the Shema (the first six words, “Hear, O Israel, the Lord our God, the Lord is One”), and uncover during the subsequent paragraphs: Deuteronomy 6:4-9 and 11:13-21, and Numbers 15:37-41. We recite the Shema in its entirety twice every day: once during shaharit (morning) service and once in ma’ariv (evening) service, and these are the only two times when it’s customary to cover our eyes. There are other times when we recite those six words; we only cover our eyes when reciting the full Shema.
The source of this practice is the Talmud, Berakhot 13b, which mentions Rabbi Judah the Prince (Yehudah HaNassi) covering his eyes to block out the distraction from his students (who quite possibly were flipping styluses or dunking their neighbors’ hair in the inkwells). (Though it is tempting to think that we hold our tzitziyot at the same time to prevent similar dunking, that is not the case. We are bringing together the “four corners of the earth” to represent bringing our people back together, and this thought morphs into the reminder in the final paragraph that tzitzit are there to remind us to do the things about which we are reading. Additionally, some have the practice of passing the tzitziyot in front of the closed eyes, but that is another topic.)
The practice of eye covering was later codified in the Shulhan Arukh (OH 61:4-5).
Of course, as our loyal readers expect, other possible explanations for the tradition have been put forth. Rabbi Ezekiel Landau of Prague (17th century) suggested that we could not completely express full faith in God while the pain of the world was in view.
There are others who feel that closing our eyes lets us leave ourselves open to looking in all directions simultaneously, the better to find God all around us. Others have opined that the only way to connect with the unified universe is by blocking out all other stimuli beyond the words one is uttering. Still others have followed a Kabbalist teaching that we should shape our covering hand into the letters shin, dalet, yad, using the three middle fingers on the forehead as the shin, a bent thumb over the right eye as a dalet, and a bent pinky over the left eye as a yad. (There are other methods of this figuring as well.) Also, some have questioned whether a person without eyesight should follow the eye-covering practice. Points have been made both pro and con.
After the first six words (or some say after the second sentence), we open our eyes and strongly affirm our dedication and conviction through the successive paragraphs.