What I mean by bits and pieces has nothing to do with body parts, but everything to do with what we are willing to accept of God.
We have a tendency to choose those aspects of God that are most appealing to us, such as, we are saved by grace and Jesus died for our sins, while refusing to accept the parts of God that tell us things about ourselves that we don't want to hear, such as, you need to change your ways and live up to your faith and stop pretending to be something that you aren't. Thus, we serve God in bits and pieces. And this was the point that Jesus was making in Matt. 7:21-23
I suspect that there is depth to this passage that you haven't perceived.
Matthew 7:13-23
13: Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14: Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
15:
Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
16:
Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
17: Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
18: A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
19: Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.
20: Wherefore
by their fruits ye shall know them.
21: Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
22: Many will say to me in that day, Lord, Lord, have we not
prophesied in thy name? and in thy name have cast out devils? and
in thy name done many wonderful works?
23: And then will I profess unto them, I never knew you:
depart from me, ye that work iniquity.
How is following this passage's admonishment to reject false prophets touting their wonderful "works" related to making ourselves a living sacrifice?
What does Jesus call these false prophets?
Workers of iniquity, or
anomia 'contempt and violation of law' - the worst thing you could call someone carrying a works-based "gospel" based on compliance to the abolished covenant.
Well, that's my take, anyway.
Victor