The Curé d'Ars on Sanctity

This is what purifies the eye of the heart, and enables it to raise itself to the true light: contempt of worldly cares, mortification of the body, contrition of heart, abundance of tears... meditation on the admirable Essence of God and on His chaste Truth, fervent and pure prayer, joy in God, ardent desire for Heaven. Embrace all this, and continue in it. Advance towards the light which offers itself to you as to its sons, and descends of itself into your hearts. Take your hearts out of your breasts, and give them to Him who speaks to you, and He will fill them with deific splendour, and you will be sons of light and angels of God. 

― St. John Vianney, the Curé d'Ars