"And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption."
How can one grieve the Holy Spirit? Who is the Holy Spirit? The New Testament says more about the Spirit that many people realize. God's giving of the Spirit is a sign of his generosity. John 3:34 says that God gives the Spirit without measure. In John 7:37-39, Jesus said that all believers who came to him would have rivers of living water flowing from within them. This, of course was all about the Holy Spirit that the Lord was to give after he was glorified.
The Spirit has a very important ministry in our lives. Peter said that all who repent and are baptized would receive the gift of the Holy Spirit. Galatians 3:2 says that we are given the Spirit through faith.
1 Peter 1:2 and 2 Thess 2:13 says that we are sanctified by the Spirit. Titus 3:5 says that we are renewed by the Holy Spirit. In other words, the Spirit effects an inner transformation in our lives. The Spirit now testifies that we are children of God (Rom 8:16). Because the Spirit has set us apart as children of God, we are to be transformed in our mind and in our lifestyle. We are to walk by the Spirit (Gal 5:16-17) and thus bear the fruit of the Spirit (Gal 5:22-23). Ephesians 6:17 says that the word of God is the sword of the Spirit, meaning that the Spirit used the word to help us wage our spiritual battle against the enemy.
Romans 8:7-9 indicates that without the Spirit we do not even have the capability to submit to God. Our fleshly nature is hostile toward God. But, through the Spirit, we have the ability to put to death the deeds of the body (Rom 8:13).
The Spirit strengthens us in this task. Romans 8:26 says the Spirit helps us in our weaknesses and intercedes for us when we cannot find the words to pray. Ephesians 3:16 says we are strengthened inwardly by the Spirit. Jesus said this would happen. Before he left this earth, he told his disciples he would send the encourager/comforter to help his disciples (John 14:16, 26; 15:26; 16:7). He wasn't going to leave them alone.
The Spirit strength, guidance and encouragement. The Spirit transforms and renews us inwardly and enables us to serve God. The Spirit has high expectations and goals for us. The Spirit wants us to be transformed in our mind and in our actions every day and every night. Whether it is our attitude, our tone of voice, our actions, our goals, it is all to be brought in line with God's purposes as he has outlined them in the Bible. When we fail to be completely transformed, it grieves the Spirit who will lead, but not force us to conform to God's will.
Our actions and speech need to reflect this transformation. Not just on Sunday, but every moment of every day. The Spirit has made us into something new. As Christians, we have been cleansed, made clean, and made new. Our lives need to reflect this.