Even though as bruised reed, stated your question is not directed at any specific denomination, and as such becomes a truth question, I feel compelled to answer your question since it, points out a common problem encountered when reading the Bible. Many Scriptures taken alone are at best confusing and at worst misleading. Your question appears to be spawned in that category.
Lets take a look at those Scriptures you quoted and see what other Scriptures can help us understand what they refer to.
All Scripture is quoted from the King James translation, unless otherwise noted.
Mark 2:21 and 22 No man also seweth a piece of new cloth on an old garment: else the new piece that filled it up taketh away from the old, and the rent is made worse. 22 And no man putteth new wine into old bottles: else the new wine doth burst the bottles, and the wine is spilled, and the bottles will be marred: but new wine must be put into new bottles.
When we also consider that Jesus was answering this specific question:
Mar 2:18 And the disciples of John and of the Pharisees used to fast: and they come and say unto him, Why do the disciples of John and of the Pharisees fast, but thy disciples fast not?
and that he prefaced the Scriptures quoted in your question with:
Mark 2:19 and 20 And Jesus said unto them, Can the children of the bridechamber fast, while the bridegroom is with them? as long as they have the bridegroom with them, they cannot fast. 20 But the days will come, when the bridegroom shall be taken away from them, and then shall they fast in those days.
We are then being directed to a specific train of thought which is that there is something much more important in that hearing what Jesus has to say; is much more important than how it is to be enacted, after his departure. Or put another way he is telling them that before they can instruct others they must themselves have the whole story. This is emphasized by verses 19 and 20.
Now we can analyze the last Scriptures in this diatribe, with a clearer understanding.
Verse 21 and 22 are used as an illustration which they would be familiar with, that being that when an un-shrunk fabric or animal skin (Goat skin was used to fabricate wineskins)
is inserted into already shrunken cloth or skins would as it shrank; instead of repairing, further ruin the old.
Why this is important to understand can be best illustrated by considering that without his resurrection, his death would have no impact. It is only his taking up his life after, everyone knew that he had died, which gives meaning to his promise of eternal life.
The proper attitude toward how the Old Testament is to be viewed in relation to the New Testament is in the following Scriptures:
Matthew 5:17and 18 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. 18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
In these two Scriptures we are taught that:
- The laws of God given in the Old Testament will always be in effect until:
Revelation 21:1 And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.
- That Jesus came to the Earth expressly to fulfill those requirements laid down by God, because we could not live up to Gods standards, but he could.
Hope this helps.