When you receive the Holy Spirit, things change, because He energises you from within

For it is God which worketh in you both to will and to do of his good pleasure (Philippians 2:13).
Some Christians, in trying to excuse their spiritual ineptitude will say, “The spirit is willing, but the flesh is weak,” quoting the Lord Jesus’ statement to Peter in Matthew 26:41, and Mark 14:38. But it wasn’t a commendation; moreover, it was before the Holy Ghost came.
Prior to receiving the Holy Spirit, Peter, though willing to stand with Jesus at all cost, couldn’t. He had said, “Master, I’ll never deny you” (Matthew 26:35). But after Jesus was arrested, when a servant girl challenged him saying, “I know you, you’re with Jesus of Galilee,” Peter denied (Matthew 26:69-70). He was intimidated, not even by the soldiers, but by a young girl. “The spirit was willing, but the flesh was weak,” because Peter hadn’t yet received the Holy Spirit.
After he received the Holy Spirit, the same Peter spoke so boldly and passionately about Jesus to the multitude. His words were so full of power and conviction that the people exclaimed, “...what shall we do to be saved?” (Acts 2:37). The Bible records that three thousand of them gave their hearts to Christ on that occasion.
When you receive the Holy Spirit, things change, because He energises you from within. He makes you willing and able to do His will. What a glorious ministry of the Holy Spirit in us as new creations!
Let’s read the opening verse again, this time, in the Amplified Translation: “…for it is God Who is all the while effectually at work in you [energizing and creating in you the power and desire], both to will and to work for His good pleasure and satisfaction and delight.” Wow! God, through the Holy Spirit, is effectually at work in you, prompting you, stirring up in you the willingness to do of His good pleasure, and energising you to perform it. Hallelujah! .