There are two separate issues I want to talk about in this post. Issue number one is the concept of being the concept of comfort and the Christian. Issue number two is the concept of numerical growth.
It has been said that you can't do anything for Christ until you get out of your comfort zone. I understand the motivation behind this. People can sometimes let their petty preferences get in the way of serving God. Unfortunately, it remains bad advice.
The concept of comfort can have various meanings. For example, I am sure my pastor is would not be comfortable letting a secular rock band perform on Sunday morning. Okay, that's fine; no one would suggest that the pastor needs to "get out of his comfort zone" on that. You may remember when the Apostle Paul considered going into the region of Bithynia, but the Spirit prevented them. Evidently, Paul did not have a comfortable feeling about going into Bithynia, though he desired to spread the gospel. The Holy Spirit has made him uncomfortable with the idea.
Something can be a good thing to do, when considered on its own. Witnessing to people is considered a good thing to do. But there is a time and a place for everything, and yielding to God's leading means allowing him to redirect your good intentions when necessary.
Beyond the issue of being UNcomfortable in a spiritual way, is being comfortable in a spiritual way. God equips us each for specific service, which, if we are trying to follow Him, we will find joy and peace in doing. The peace is spiritual comfort in ministering in the way you have been enabled.
Telling people that they have to get out of their comfort zone to serve God encourages people to go against what might be the leading of the Spirit. God gives us peace about doing right and warns us about doing wrong. When we ignore our reservations or give up our contentment with where God has us as so much selfish comfort, we can get ourselves into trouble.
The truth of the matter is that we then set ourselves up against whatever standard of service is being advanced in the name of "getting out of your comfort zone." If the pastor says "you need to get out of your comfort zone and do X, Y, and Z," you'll cast aside any critical thought, adverse leading, or reservation because the pastor has implicitly labeled those as selfish hindrances keeping you in "your comfort zone." Few people will stop and question the unstated assumption that any reason for not doing X, Y, and Z constitutes an excuse for staying "comfortable." It is a form of manipulation. Biblical exhortation motivates through the word of God, not rallying people, or manipulating people, or short-circuiting people's critical thinking, or psyching people up.
The second issue pertains to the issue of numerical growth. It has also been said that evangelism is how God grows the church numerically. It may be the source of growth, but it cannot be the main purpose of evangelism. Anything is judged by how it serves its purpose. If evangelism does not result in a sufficient quantity of results, then there is a problem, if the purpose of evangelism is to grow the church numerically. And increasingly, such a problem has to be solved through promotions and other gimmicks, or through brute force in getting more people out. Evangelism's main purpose is witness. We are witnesses of Christ. We sow the seed through our witness and God causes the harvest to come in His time. We plant and water and God gives the increase. He doesn't ALWAYS give increase. He isn't OBLIGATED to give increase. Insisting that evangelism is a means of increase turns the true purpose of evangelism on its head and demands of God what He never promised to consistently provide. More tragically, it changes the motivation for evangelism from love for a lost world to a desire to grow the church.
Sadly, even the most exegetical of teachers can end up with cliché theology. "Sin will keep you from this book, and this book will keep you from sin" theology. "Attempt great things for God, expect great things from God" theology. Little sound bites for a sound bite world that line up with Scripture loosely and imperfectly. Man's wisdom espoused without constantly and consistently setting it within the context of Scripture is a road that slowly transforms a community of believers from Bible-based to man-based, from a community based on faithful teaching to a community focused on the stature of the organization called "church". Perhaps the pastor expects people to understand the context automatically. To understand his heart? But how soon are we all want to substitute our comprehension of God and Scripture for God and Scripture themselves. It is more convenient.
…and often more conducive for pushing the church in the direction of quantitative growth, be that attendees or buildings or whatever. The growth of any church is none of anybody’s business. God will grow it when He is ready.