How do you know if your faith is as strong as you think it is? Paul reminds us in Philippians 3:13-14, "Brothers and sisters, I do not consider myself yet to have taken hold of it. But one thing I do: Forgetting what is behind and straining toward what is ahead, 14 I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus." Spiritual Complacency can creep up on us quickly, so we have to choose Christ daily and strain (work, effort) toward what is ahead of us and not let the past hinder what God has for us now. Because if you’re not dead you’re not done.
To regain a vibrant faith, we need to spend time with God: read His Word, record and reflect on it, respond to it, and repeat what you've learned by telling others.