Gen 1:3

1:3 God said. God’s free act of creation through the divine Word (Ps. 33:6, 9; cf. John 1:1, 3) signifies that the universe is not an emanation or part of the divine being, thus ruling out all forms of pantheism. Though creation is not part of God’s being, all creation is utterly dependent on God for its existence, for He creates and sustains all that is by the power of His own being.

Let there be. God’s will is irresistible. It is carried out by divine imperative.