(1) יהוה called to Moses and spoke to him from the Tent of Meeting, saying:
יהוה is calling to Moshe. The verb קרא means to call out, summon (to a locale, or specific position) or to pray when the preposition is pointing to a name (i.e. t לקרוא בשם יהוה).
Did יהוה pray to Moshe? Did he humbly open the book of Leviticus to show us how prayer is supposed to work? Is prayer bidirectional? What is prayer? Is the name of the book, "And he prayed..."
What a dream come true! Call out to me יהוה! Summon me and call me by name into your tent of meeting! I desire to meet with you. How do I make an appointment with you? Were you teaching Moshe how to teach Yisrael how to make appointments? Is the whole point of Leviticus to draw us into meeting with you? What are you trying to show us? Call out to us the way you called out to Moshe! Everyone reading this text, call out to them!
ויקרא...וידבר...
Prayer is just talking WITH יהוה! It is just talking, but who am i "just" talking to? The kind of person the God of Israel is requires a particular approach. The Torah is about to teach us how to approach Yahweh whether we are meeting him inside his tent or out in our own tent. Leviticus is going to teach us how to approach, how to pray, how to address, how to converse with Yahweh. IT WILL TAKE ALL THAT YOU HAVE.