Ephesians 6:10

In conclusion, be strong in the Lord (draw your strength from Him and be empowered through your union with Him) and in the power of His (boundless) might.

Building up strength doesn’t happen overnight. When we practice the word of God, we build up trust and strength in what we believe. We see God working through His word on our behalf when we pray and believe. Weak faith will not see the same result because it hasn’t developed a faith relationship with God.