1 Thessalonians 5:18 in everything give thanks for this is the desirous will of God in Christ Jesus unto you.
Thankfulness is an attitude of gratitude due to a favorable disposition towards someone. Within the Christian life, thankfulness comes from being filled by the Holy Spirit, while speaking psalms, hymns, and spiritual songs to yourself, singing and making melody in your heart to the Lord, which results in giving thanks in all things to God (Ephesians 5:18-20).
Because humans were not thankful, did not have a favorable opinion of God, even during a time when they all knew God, we see the impact today of the mind turning to futility with theories that are preposterous being presented as factual, such as evolution and false religions, along with the rejection of truth in every aspect of life. These all come from a lack of appreciation for what God provided for them (Romans 1:21). In the same way, when we are not seeking to fulfill the desires of the Spirit, we forget to be thankful for what God provides for us and lose sight of the fact that we have been washed from our sins while going back to wallowing in the filth of the old man like a dog returning to its vomit (2 Peter 1:9; 2:22).
It is a thankful thing that even though we still have a sin nature, that will manipulate us into doing wrong if we seek to live by law, because we live out from faith we have freedom from it in Christ and therefore with the mind we serve the law of God, but with the flesh the law of the sin nature (Romans 7:25). Now there is no condemnation in Christ Jesus (Romans 8:1) and when we walk by the Spirit, we fulfill the law of the Spirit of life in Christ Jesus that frees us from bondage to sin (Romans 8:4). We live by grace through faith, which makes the sin nature ineffective because it cannot work out what it desires (Galatians 5:17-18). Even though we struggle, we are able to overcome sin in our lives because of what God has done for us in salvation and understanding this will result in an expression of gratitude because of the favorable disposition we have towards God so that we are thankful in all things and for all things.
We see a proper attitude towards troubles in our lives through our Lord Jesus, for on the night in which He was betrayed, knowing what was coming, He gave thanks to God and left us a remembrance of Him in what we refer to as communion (1 Corinthians 11:24). Why would He be thankful in this situation? It was because of His favorable attitude towards God the Father, Whom He knew would keep His Word and save Him from death (Hebrews 5:7).
Since thankfulness is rooted in being Spiritual, when we lack a favorable temperament, it is because our mind is not focused on the truth, and we are not seeking to fulfill the desirous will of God in our lives. The reason we would seek God’s will over ours is because all things work for good for those who are loving God, for He wants us to be happy (Romans 8:28) and producing righteousness so that our works are good. This is true even when being child-trained for our disobedience (Hebrews 12:10-11). Therefore, let us be thankful in all things and for all people, not looking at the situation we face, but at the promises that God has given us so that even through tribulation, sickness, disease, death, life, prosperity, happiness, or any other state we find ourselves in, we can truly be thankful because God will never leave us nor forsake us, and we are more than conquers through Him Who loves us (Romans 8:37; Hebrews 13:5).
