When Jesus was questioned by the scribes of the Pharisees about how His practices differed from those of John the Baptist, He gave three similar illustrations to teach the newness of His teaching and practice.
And Jesus said to them, “Can the wedding guests fast while the bridegroom is with them? As long as they have the bridegroom with them, they cannot fast. The days will come when the bridegroom is taken away from them, and then they will fast in that day. No one sews a piece of unshrunk cloth on an old garment. If he does, the patch tears away from it, the new from the old, and a worse tear is made. And no one puts new wine into old wineskins. If he does, the wine will burst the skins– and the wine is destroyed, and so are the skins. But new wine is for fresh wineskins.” (Mark 2:19-22 ESV)
The third illustration is about putting new wine into old wineskins. As the wine ferments it expands and stretches the wineskin. If an old wineskin is used, the expansion will cause the wineskin to explode.
Our photo below shows an animal skin being use for churning, but it is easy to understand wine being placed in an animal skin like this.
Instead of using stone jars for storing new wine, Klinck says,
More likely, however, they would use wineskins for this purpose. These are the “bottles” of the Bible. A wine bottle was made out of a goatskin, sewn together where it had been cut to remove it from the carcass. This formed a sack that could be tied at the neck and hung up. The resilience of the new rawhide took up whatever expansion might result from the process of fermentation. Of course, no one would think of putting “new wine into old wineskins,” since the old dried and cracked skins from the previous year were unsafe (Matthew 9:17). (Klinck and Kiehl, Everyday Life in Bible Times, p. 54).
The Gibeonites tricked the Israelites with old wineskins that were “worn-out and torn and mended” (Joshua 9:4). They claimed that the wineskins “were new when we filled them, and behold, they have burst” (Joshua 9:13 ESV)
Elihu used the same illustration in defense of his much speaking.
I also will answer with my share; I also will declare my opinion. For I am full of words; the spirit within me constrains me. Behold, my belly is like wine that has no vent; like new wineskins ready to burst. I must speak, that I may find relief; I must open my lips and answer. (Job 32:17-20 ESV)