The apostle speaks with admiration about the great significance of Christians: from now on, we are children of God (2), and we are conformed to the image of the Son (cf. Rom 8:29). All of this is a gift and grace of his love.
The Father has ‘given’ us—as a grace and sign of his goodness—to become participants in the divine nature, thereby revealing to us the immeasurable extent of his infinite love (1; 2 Pt 1:4). Those who hold this hope are purified and freed from anxiety and existential pessimism. They live in gratuitousness.