The Bible shows various ways that believers can grow in and be built up in faith. Naturally the number one way to do this is found in Romans 10:17 So then faith comes by hearing, and hearing by the word of God. This is not to mean everyone who hears the Word of God responds favorable to it. It means that faith is present in the Word of God. When the Word of God read, studied, meditated upon, taught and preached faith is present. However, Acts 14:6-10 shows us an interesting situation. Out of a crowd of people who heard the Word of God preached, only one man received the Word and was healed. The explanation of Parable of the soils by Jesus also bears witness to this point. Not everyone believes it, receives it and retains it. However, the more of the Word that believers hear, the more faith will grow. Not just reading it, but studying and especially meditating on His Word daily grows faith.
Romans 12:3 reveals to us that "God has given every believer a measure of faith." 1 Corinthians 12:9 The Apostle Paul presents nine supernatural gifts of the Holy Spirit in which the "gift of faith" is one. It is no more difficult to receive the gift of faith than it is to receive any other gift. How do we know this?
1 Corinthians 12:7, 11 tells us that the manifestations of these gifts are distributed to any believer at any time as the Holy Spirit wills. The Holy Spirit gives supernatural faith at times to accomplish the impossible as He wills. Also I Corinthians 14:1 tells believers to desire spiritual gifts (plural) because they are an advantage for the common good of all.
Next we see that within Galatians 5:22-23 among the "Fruit of the Spirit" is faithfulness. It is the same Greek word that is translated faith elsewhere. The Holy Spirit is at work in us growing faith in our lives.
According to James 1:22, 2:14-18 "faith without corresponding actions is dead." Faith also grows by putting action to God's Word. For instance, if I truly believe that Gods will is to heal, then I put action to that by laying hands on people and pray for healing. Last but certainly not least Jude 20 tells us that by "praying in the Holy Spirit," that is our pray language, an unknown tongue, believers can "build themselves up in faith."
So, if a believers faith does not grow, it is certainly not Gods fault. His Word increases our faith, He has given every believer a measure of faith, the Holy Spirit manifests the gift of faith and the fruit of faith, our faith grows when we act upon Gods Word and we build up our faith through praying in the Holy Spirit. However, this all hangs upon what each individual believers understands or misunderstands about God. If believers do not believe (interesting thought) certain things that the Word of God says are true, then they limit their faith from growing and releasing the things that God has given to the church and every believer. Honestly, how can a believer even think that God's Word does not work today like it did in the early church. The only way that happens is that some how God has changed, HE DIDN"T, His will has changed, IT DIDN'T or just maybe believers have been taught to doubt by leaders who have no faith, MOST LIKELY. So let's exercise our faith and get ourselves pumped up in HIM!