What is a biblical view of thankfulness / gratitude?

from the old testament

• Many of the Psalms give thanks to God, providing a model for believers to follow (Psalms 95:1-2, 100:4, 103:1-2, 107:1-2).
• Even after learning of an irrevocable ordinance that said anyone worshiping God would be cast into the lion’s den, Daniel still maintained his daily habit of giving thanks to God in prayer with his window open for anyone to see (Daniel 6:10). Believers should never allow any man-made law or cultural pressure to prevent us from thanking God.

from the new testament

• We should thank God for all He provides for us. He has given us life and blesses us with much more beyond that (Matthew 6:25-34).
• Far beyond material blessings, we are thankful to God for His spiritual blessings. Foremost is His gift of salvation. Apart from Jesus Christ we only deserve eternity in hell (John 3:16-18).
• God has given us His Holy Spirit to indwell us (John 14:16-17). We are beyond privileged to receive this incredible gift. We can thank Him for His intimate presence in our lives.
• While we were still God's enemies, dead in our sins, He sent His Son, Jesus Christ, to make atonement for us (Romans 5:10). Giving thanks to God for that is good and right.
• We are heirs of God and co-heirs with Christ (Romans 8:17). That our identity has changed from slaves to sin to royal heirs with Christ is something we should express gratitude to God for.
• We can even be thankful under trials because God works even bad things for good those who love Him (Romans 8:28). Since the ultimate goal of the Christian is to be conformed to the image of Christ, God can use trials and tribulations to grow us and mold us into Christ’s likeness. He can also use them to make us more reliant on His strength and to test and purify our faith.
• The spiritual blessings we receive from God are infinite, and each one is a cause for gratitude. All that we have been freely given by God through our union with Christ should cause us to cry out, "Thanks be to God for his inexpressible gift!" (2 Corinthians 9:15).
• Salvation involves more than rescue from hell; God has forgiven our sins, adopted us into His family, and blessed us with eternal life (Ephesians 1:3-14). That should compel us to thank Him.
• We ought to thank God for what He is doing through even the most painful circumstances of our lives. Even in death a Christian can give thanks, for death brings the believer the gain of being brought immediately into the presence of Jesus (Philippians 1:21-23).
• First Thessalonians 5:16-18 says, "Rejoice always, pray without ceasing, give thanks in all circumstances; for this is the will of God in Christ Jesus for you." Clearly, thankfulness should be characteristic of Christians. Thankfulness is also so crucial to the Christian life that we are commanded to do it always and in every circumstance.
• During trials, temptations, and tribulations we should thank God (James 1:1-4). This is one of the most important lessons for a Christian to learn if he or she would be truly joyful, content, and peaceful.
• God has equipped us with all we need for life and godliness (2 Peter 1:3-4). This is a blessing we should express gratitude for.

implications for today

Giving thanks to God is of such fundamental importance that the Bible mentions the failure to do so as part of the basis for God's judgment against mankind (Romans 1:21). We have so many reasons to thank God, yet doing so is far too rare because complaining and grumbling come easily to us. We do well to realize that God owes us nothing yet has graciously given us all things in Jesus Christ (Romans 8:31-32; Ephesians 1:3-14; 2 Peter 1:3). Jesus pointed out both the importance and the rarity of thanksgiving when only one of the ten lepers that He healed returned to thank Him. We should imitate the gratefulness of that one leper (Luke 17:11-19). In a spiritual sense, we are all born lepers with the disfiguring and alienating disease called sin. Yet, Christ voluntarily took on our “disease,” the bruises due our iniquities, and the stripes due our sins. Thankfulness is the only proper response to such lavish grace. Our lives and every good thing in them are gifts from God (James 1:17), and a proper understanding of God's providence in working all things together for the good of those who love Him is a bedrock of thanksgiving as well as the antidote for ingratitude and complaining (Philippians 2:14-16). We have done and can do nothing to deserve His gifts—both material and immaterial, yet the eternal life that we have received through faith in Jesus calls for an eternity of gratitude (John 3:15).