Luke 15:7

Joy in heaven, &c. What incitement ought it not to be to us to practice virtue, when we reflect that our conversion causes joy to the troops of blessed spirits, whose protection we should always seek, and whose presence we should always revere. (St. Ambrose) --- There is greater joy for the conversion of a sinner, than for the perseverance of the just; but it frequently happens, that these being free from the chain of sin, remain indeed in the path of justice, but press not on eagerly to their heavenly country; whilst such as have been sinners, are stung with grief at the remembrance of their former transgressions, and calling to mind how they have forsaken their God, endeavour by present fervour to compensate for their past misconduct. But it must be remembered that there are many just, whose lives cause such joy to the heavenly court, that all the penitential exercises of sinners cannot be preferred before them. (St. Gregory, hom. xxxiv.)