John Wesley on Luke 15:31

Thou art ever with me, and all that I have is thine - This suggests a strong reason against murmuring at the indulgence shown to the greatest of sinners. As the father's receiving the younger son did not cause him to disinherit the elder; so God's receiving notorious sinners will be no loss to those who have always served him; neither will he raise these to a state of glory equal to that of those who have always served him, if they have, upon the whole, made a greater progress in inward as well as outward holiness.