When Moses reached the summit with the new tablets, the meeting was unlike the first Sinai revelation. Targum Pseudo-Jonathan, the Aramaic paraphrase of the Torah, describes what happened.
"The Lord revealed Himself in the cloud of the glory of His Shekhinah, and Moses stood with Him there; and Moses called on the Name of the Memra, the Word of the Lord" (Exodus 34:5).
Notice the reversal. In the earlier chapters, God had called Moses. This time, Moses calls on God. The prophet initiates the invocation. He pronounces the Name. He begins the liturgy that will become the heart of Jewish prayer.
The Aramaic qera b'shuma di-Memra, "called on the Name of the Word," carries forward a theological move central to the Targum. God is Memra, the divine Word, the Agency by which Heaven acts in the world. Moses does not call on an abstraction. He calls on the active, speaking Presence, the same Word that has been following him through the whole Sinai drama.
And the cloud that descended was not a show of force. It was the Shekhinah of glory, present but veiled, granting the audience for what was about to be revealed - the Thirteen Attributes, the liturgical foundation of every Selichot service for the next three thousand years.
Takeaway: Prayer at its deepest is not waiting for God to call us. It is learning to call on the Name, to enter the cloud, to begin the conversation ourselves.