"All people desire what they believe will make them happy. If a person is not full of desire for God, we can only conclude that he is engaged with another happiness"

This quote by William Law talks to the concept that all individuals prefer what they believe will make them pleased. He suggests that if a person is not full of desire for God, then they should be engaged with another source of joy. This suggests that God is the supreme source of happiness, which if a person is not seeking God, then they are seeking something else. This might be material belongings, relationships, or any other source of enjoyment. Ultimately, Law is suggesting that if a person is not looking for God, then they are not looking for true and lasting happiness. He is motivating individuals to seek God, as He is the only source of real and enduring delight.