Sin is ugly as it takes us away from God and our neighbour. Mercy is a two way street; you cannot receive mercy unless it is offered. You cannot offer mercy unless there is someone to receive it, therefore, God waits for us to be ready to receive his mercy.
“Redeem me, O Lord, and have mercy on me. My foot stands on level ground; I will bless the Lord in the assembly.” (Cf. Ps 25: 11-12)