One of the Bible's greatest truths is that when we come to Christ and commit our lives to Him, He comes to live within us by His Holy Spirit. In fact, the Bible warns, "If anyone does not have the Spirit of Christ, he does not belong to Christ" (Romans 8:9). If you know Jesus, the Holy Spirit already lives within you -- whether you feel His presence or not.
Why has He been given? The Bible gives several reasons -- but behind them all is our need for God's help. The Holy Spirit, the Bible says, "helps us in our weakness" (Romans 8:26). He convicts us of sin, He opens our eyes to God's truth, He grants us spiritual gifts, He counsels and guides us -- all these and more would be impossible without His help.
Never forget that the Holy Spirit isn't an impersonal force or power (like electricity or gravity); He is God. Think of it: God Himself now dwells within you if you know Christ! Jesus said, "I will ask the Father, and he will give you another Counselor to be with you forever -- the Spirit of truth" (John 14:16-17). Because He lives within us, we can ask God to help us in our times of need, and to give us the courage and strength to live as we should.
Don't try to live the Christian life in your own strength; if you do, you will only fail. Instead, trust the Holy Spirit to give you the wisdom and strength you need.