To “rely on the Spirit” means we trust the Spirit. To trust the Spirit means that at all times you accept and believe the Holy Spirit’s interpretation of your situation and the Holy Spirit’ instruction on how to respond.
And since the Holy Spirit is part of the Godhead, we need not guess about what the Spirit’s opinion on our lives is. The Bible is the Holy Spirit’s view on all things. Or other way around, the Spirit’s view is nothing more and nothing less than what the Scripture-He-inspired says (2 Peter 1:20-21).
When you see sin, let’s say the sin of worry, in your life, then “rely on the Spirit” in your struggle against worry by believing that the Spirit says worry is a grievous sin against a caring and sovereign God (Matthew 6:25-31). Also, “rely on the Spirit,”and not on your own excuses or the world’s opinions, by understanding that thankful trust in God is the Spirit’s answer to your problem of worry (Philippians 4:6).
To rely on the Spirit means living God’s Way in God’s World.
Dear Christian, let us walk by the Spirit’s instruction in Scripture, for then we will not fulfil the desires of the flesh (Galatians 5:16).