“O Lord, in the morning you hear my voice; in the morning I prepare a sacrifice for you and watch” (Psalm 5:3 ESV)

This is more an expression of resolve by the petitioner than an expectation that the Lord will hear the petition. “O Lord, in the morning [and every morning thereafter] you [will] hear my voice.” The psalmist David is expressing his determination to begin his days in prayer. He uses metaphoric language in the Hebrew to describe how he will pray. He speaks like an archer, saying “I will send my prayer towards You and to You alone, and watch to see that it hits the target.” Or like a priest, David plans to “prepare” his prayer like a morning “sacrifice,” arranged carefully upon the altar, and then, to watch the smoke arise to the throne of heaven. David is determined to begin his days in the offering up of prayers to God. These will not be sleepy, memorized mutterings, but carefully considered and arrayed prayers… prayers aimed at the heart of God.