What does Daniel 9:19 mean?
Three times Daniel prays, "O Lord." Some commentators believe this three-times-repeated phrase alludes to the Trinity: God's existence as one Being and yet three divine Persons referred to as the Father, Son, and Holy Spirit. That is possible, but Daniel's revelations are much more focused on prophecy than exploring the nature of God. Each time Daniel addresses the Lord, he offers a petition for the Lord to "hear," to "forgive," and to "pay attention and act." A fourth petition follows his call upon God. He prays, "Delay not, for your own sake."Daniel asks for forgiveness (Daniel 9:5, 9). He does not blame the Lord for the tragedies that befell Jerusalem; he realizes Israel's sins brought those calamities (Deuteronomy 28:15–24, 48–50; 29:25). So, he asks for forgiveness. He does not tell the Lord what to do, but simply asks Him to act because Jerusalem and Israel are called by God's name. He is concerned for God's reputation. Psalm 48:1 identifies Jerusalem as "the city of our God," and "His holy mountain." In Jeremiah 25:29 the Lord refers to Jerusalem as "the city that is called by my name."
This ends Daniel's prayer on this subject. In the next verse, he will receive divine explanation of Israel's future. This will be delivered by the angel Gabriel (Daniel 9:20).