How is it inconsistent, specifically. In many ways, God requires more from those of us in the age of Grace. Jesus addressed the heart issues, not merely robotic obedience to the law. Paul belabored this point as well.
I agree it was more an issue of growth. The first step in raising a child is obtaining simple obedience, evidenced by this common sentiment "Because I said so, thats why" That is a fine answer for a 2 year old, but as children get older you have to start addressing the heart attitudes, or when they no longer are afraid of the consequences that you can bring to bear, they may very well stop obeying outwardly as well. God has moved through history to reveal many of his attributes to us, and has demonstrated the consistency of all of his attributes and the balance between such issues as his justice and his mercy. Jesus said we must exceed the righteousness of the religious rulers of his day.
Mat 5:21-22
(21) Ye have heard that it was said by them of old time, Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment:
(22) But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.
Mat 5:27-28
(27) Ye have heard that it was said by them of old time, Thou shalt not commit adultery:
(28) But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.