Rav Eliyahu Lopian zt”l wrote in his Lev Eliyahu (vol. 3, p. 320): When a person stands to pray the Shemoneh Esrei, he recites the introductory pasuk (Tehillim 51:17), ‘ שְׂפָתַי תִּפְתָּח וּפִי יַגִּיד תְּהִלָּתֶֽךָה - Hashem, open my lips, and my mouth shall declare Your praise. Rav Yonasan Eybeschütz zt”l explains in Yaaros Devash the reason for this. When a person reflects upon before Whom he is now standing in prayer—“Know before Whom you stand”—he should be gripped by great fear, and it is possible that from the intensity of that fear he will be unable to open his mouth. Therefore, he precedes the prayer with the request “Hashem, open my lips”—meaning, assist me so that I will be able to open my mouth and speak before You.
He then brings an incident he remembered from his youth, which had once become widely known throughout Russia during the days of Czar Nicholas. The czar had commanded a master contractor to construct a major road in the capital city. The king later traveled upon the road and was greatly pleased by it, and summoned the contractor to the palace to speak with him.
But when the contractor appeared before the king, he was seized with fear and trembling; the sinews of his tongue tightened, and he was unable to utter a single sound from the overwhelming fear—remaining mute for the rest of his life!
If so, all the more so when a person stands before the King of kings, the Holy One, blessed is He. If he would contemplate carefully before Whom he is standing, he might be seized with great trembling and fear and be unable to speak at all. Therefore, he begins with the plea, “Hashem, open my lips.”
Woe unto us from the Day of Judgment; woe unto us from the Day of Rebuke!
