The bottom line is that only God can clarify what a church should do in all its spending and planning. However, there are a few important things that can be agreed on.
It is reasonable for a church to plan ahead and to be sensitive to the growing needs of the church family. It is also reasonable to imagine what could be accomplished in reaching others for Jesus Christ if the facilities were available. Many church growth experts believe that when a church grows to 70-80% of capacity, it will not sustain any more growth without plans for expansion.
A church can fall into materialism when it begins to value things more than people. If a new building program is for the pride of its membership rather than the effectiveness of its ministry, then the church is in danger of a bad building program. In all things, the church must desire that Christ be lifted up and that the lost are reached and that the saved be discipled to the glory of God.
The church is not a building but the people whom God has ransomed and made a part of His family. Often God sees fit to bless a family with growth in numbers. When a family grows in numbers, it usually considers whether or not there is room in the present facilities. If there is not enough room, an addition is one option, as is a different house altogether. The facilities ought to be designed in such a way to facilitate the needed functions of the household and not just a monument to the family’s greatness. For a church to truly be expanding physically in a godly manner, it must be sure its motive is to be used of God to build up the body of Christ and assist in the building up of the universal church of Jesus Christ. In other words, every ministry needs to be “mission” not “market” driven.
The Word of God tells us that the only way to do any building is to base it on our relationship to Jesus Christ (1 Corinthians 3:11-15). One of the biggest pitfalls in building bigger is the issue of pride and misplaced priorities (Psalm 127:1). Remember the parable of the rich man in Luke 12:16. We should never put our faith in things or believe that somehow what God gives us we have earned or are able to keep for ourselves.
You can be sure that if God wants your church to expand, He will bring leadership, unity, and resources. If those are not present, it is reasonable to take a step back and reconsider the direction. There is nothing in the Bible against a church expanding physically. The question is in the timing, motive, and purpose for the building. God is more glorified in the church being obedient to Him and growing spiritually than He is in the church expanding physically. Remember, that which is not of faith is sin; therefore, only be involved if you have searched for God’s will and believe you know what He is asking you to do (Romans 14:23).