Spiritual discomfort, being stretched to new limits and unknown territory is an alarming experience, whether you are a "seasoned" Christian or one who has just discovered Jesus as your Savior. Jesus himself taught that "new wine is put into fresh wineskins, and so both are preserved." Wine skins in bible times were goatskins. They used new skins for fermenting new wine so that over time as the wine went through its aging process the skins could adjust to the process of the chemical change by slowly stretching making room for the wine's maturation. If they had put the new wine in old, used skins, the skins would have burst because they were not pliable and flexible to handle the pressure of the wine aging process. Similarly, when God calls us to "new horizons", be them a first call to living a Christian life or a tenth call to serve in a missionary capacity, we need to remember to put on "new skin" so that we can be flexible & pliable to handle the pressure of the change, opposition, criticism, second-guessing, and temptation to backslide that may come along with "new horizons". And remember that it takes time for "new wine" to become "good wine"(see John 2:1-12).
Beautiful song on YouTube about this topic: New Wine by Hillsong.
"Neither is new wine put into old wineskins. If it is, the skins burst and the wine is spilled and the skins are destroyed. But new wine is put into fresh wineskins, and so both are preserved." Matthew 9:17