Why is being filled with the Holy Spirit important?

The filling of the Holy Spirit is essential for Christians as it enhances their ability to live in accordance with God's calling. In Acts 4:31, when the apostles were filled with the Holy Spirit, they spoke the word of God with boldness, showcasing that the Spirit empowers believers for both righteous living and effective witness. This divine filling not only transforms how believers engage with the world but also fosters unity among them, as seen when 'the multitude of them that believed were of one heart and one soul'. The work of the Holy Spirit is vital for sanctification and successful ministry.