Here are just a few verses dealing with Thanksgiving. This is by no means an exhaustive study: it’s just a result of looking up “thanks” and “thanksgiving” in an online concordance. Many of the passages would fit under multiple headings and I am sure there are others that could be added. But this is a good start. It would be profitable to study many of these verses within the context of the passages they came from.

And when ye will offer a sacrifice of thanksgiving unto the LORD, offer it at your own will. Leviticus 22:29.

As ye have therefore received Christ Jesus the Lord, so walk ye in him: Rooted and built up in him, and stablished in the faith, as ye have been taught, abounding therein with thanksgiving. Colossians 2:6-7.

It is a sacrifice:

By him therefore let us offer the sacrifice of praise to God continually, that is, the fruit of our lips giving thanks to his name. Hebrews 13:15.

It is often a testimony to others of God’s person and work:

That I may publish with the voice of thanksgiving, and tell of all thy wondrous works. Psalm 26:7

I will praise the name of God with a song, and will magnify him with thanksgiving. This also shall please the LORD better than an ox or bullock that hath horns and hoofs. Psalm 69:30-31.

Ye also helping together by prayer for us, that for the gift bestowed upon us by the means of many persons thanks may be given by many on our behalf. II Corinthians 1:11.

For all things are for your sakes, that the abundant grace might through the thanksgiving of many redound to the glory of God. II Corinthians 4:15.

For the administration of this service not only supplieth the want of the saints, but is abundant also by many thanksgivings unto God; Whiles by the experiment of this ministration they glorify God for your professed subjection unto the gospel of Christ, and for your liberal distribution unto them, and unto all men; And by their prayer for you, which long after you for the exceeding grace of God in you. II Corinthians 9:12-14.

And all the angels stood round about the throne, and about the elders and the four beasts, and fell before the throne on their faces, and worshipped God, Saying, Amen: Blessing, and glory, and wisdom, and thanksgiving, and honour, and power, and might, be unto our God for ever and ever. Amen. Revelation 7:11-12.

Give thanks unto the LORD, call upon his name, make known his deeds among the people. Sing unto him, sing psalms unto him, talk ye of all his wondrous works. I Chronicles 16: 8-9.

And say ye, Save us, O God of our salvation, and gather us together, and deliver us from the heathen, that we may give thanks to thy holy name, and glory in thy praise. I Chronicles 16:35.

So we thy people and sheep of thy pasture will give thee thanks for ever: we will shew forth thy praise to all generations. Psalm 79:13.

It is a good thing to give thanks unto the LORD, and to sing praises unto thy name, O most high: To shew forth thy lovingkindness in the morning, and thy faithfulness every night. Psalm 92:1-2.

Often coupled with joy and singing:

And at the dedication of the wall of Jerusalem they sought the Levites out of all their places, to bring them to Jerusalem, to keep the dedication with gladness, both with thanksgivings, and with singing, with cymbals, psalteries, and with harps. Nehemiah 12:27.

Give thanks unto the LORD, call upon his name, make known his deeds among the people. Sing unto him, sing psalms unto him, talk ye of all his wondrous works. I Chronicles 16: 8-9.

Serve the LORD with gladness: come before his presence with singing. Know ye that the LORD he is God: it is he that hath made us, and not we ourselves; we are his people, and the sheep of his pasture. Enter into his gates with thanksgiving, and into his courts with praise: be thankful unto him, and bless his name. Psalm 100:2-4.

Sing unto the LORD with thanksgiving; sing praise upon the harp unto our God. Psalm 147:6.

Therefore will I give thanks unto thee, O LORD, among the heathen, and sing praises unto thy name. Psalm 18:49

Psalm 93:1-3;

Often coupled with prayer:

Offer unto God thanksgiving; and pay thy vows unto the most High: And call upon me in the day of trouble: I will deliver thee, and thou shalt glorify me. Psalm 50:14-15.

I will offer to thee the sacrifice of thanksgiving, and will call upon the name of the LORD. Psalm 116:17.

Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God. And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus. Philippians 4:6-7.

Continue in prayer, and watch in the same with thanksgiving. Colossians 4:2.

Cease not to give thanks for you, making mention of you in my prayers. Ephesians 1:16.

A result of meditating on God’s Word:

Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord. And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him. Colossians 3:16-17.

A result of being filled with the Spirit:

And be not drunk with wine, wherein is excess; but be filled with the Spirit; Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord; Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ; Submitting yourselves one to another in the fear of God. Ephesians 5:18-21.

Reasons to thank the Lord:

It’s commanded:

Enter into his gates with thanksgiving, and into his courts with praise: be thankful unto him, and bless his name. Psalm 100:4.

Continue in prayer, and watch in the same with thanksgiving. Colossians 4:2.
His greatness, His creation:

O come, let us sing unto the LORD: let us make a joyful noise to the rock of our salvation.
Let us come before his presence with thanksgiving, and make a joyful noise unto him with psalms.
For the LORD is a great God, and a great King above all gods.
In his hand are the deep places of the earth: the strength of the hills is his also.
The sea is his, and he made it: and his hands formed the dry land.
Psalm 95: 1-5

Oh that men would praise the LORD for his goodness, and for his wonderful works to the children of men! And let them sacrifice the sacrifices of thanksgiving, and declare his works with rejoicing. Psalm 107:21-22.

His comfort:

For the LORD shall comfort Zion: he will comfort all her waste places; and he will make her wilderness like Eden, and her desert like the garden of the LORD; joy and gladness shall be found therein, thanksgiving, and the voice of melody. Isaiah 51: 3.

His bountiful supply:

Being enriched in every thing to all bountifulness, which causeth through us thanksgiving to God. II Corinthians 9:11.
His unspeakable gift:

Thanks be unto God for his unspeakable gift. II Corinthians 9:15.

Meat:

Forbidding to marry, and commanding to abstain from meats, which God hath created to be received with thanksgiving of them which believe and know the truth. For every creature of God is good, and nothing to be refused, if it be received with thanksgiving: For it is sanctified by the word of God and prayer. I Timothy 4:3-5; Matthew 15:36

Deliverance from enemies:

And that bringeth me forth from mine enemies: thou also hast lifted me up on high above them that rose up against me: thou hast delivered me from the violent man. Therefore I will give thanks unto thee, O LORD, among the heathen, and I will sing praises unto thy name. II Samuel 22:49-50

And say ye, Save us, O God of our salvation, and gather us together, and deliver us from the heathen, that we may give thanks to thy holy name, and glory in thy praise. I Chronicles 16:35.

Psalm 18:48-50

His goodness:

O give thanks unto the LORD; for he is good; for his mercy endureth for ever. I Chronicles 16:34; Ezra 3:11; Psalm 106:1; 107:1; 118:1, 29; 136.

His holiness:

Sing unto the LORD, O ye saints of his, and give thanks at the remembrance of his holiness. Psalm 30:4.

His deliverance from sorrow:

Thou hast turned for me my mourning into dancing: thou hast put off my sackcloth, and girded me with gladness; To the end that my glory may sing praise to thee, and not be silent. O LORD my God, I will give thanks unto thee for ever. Psalm 30:11-12

His righteous judgments:

At midnight I will rise to give thanks unto thee because of thy righteous judgments. Psalm 119: 62.

Victory over death:

The sting of death is sin; and the strength of sin is the law. But thanks be to God, which giveth us the victory through our Lord Jesus Christ. I Corinthians 15:56-57.

Causing us to triumph, making Himself known through us:

Now thanks be unto God, which always causeth us to triumph in Christ, and maketh manifest the savour of his knowledge by us in every place. II Corinthians 2:14.

His working through other people:

But thanks be to God, which put the same earnest care into the heart of Titus for you. II Corinthians 8:16.

Cease not to give thanks for you, making mention of you in my prayers. Ephesians 1:16.

We give thanks to God and the Father of our Lord Jesus Christ, praying always for you, Since we heard of your faith in Christ Jesus, and of the love which ye have to all the saints. Col. 1:2-4

I Thessalonians 1:1-3; 3:9-10; II Thessalonians 2:13-14.

Saving us:

Giving thanks unto the Father, which hath made us meet to be partakers of the inheritance of the saints in light: Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son: In whom we have redemption through his blood, even the forgiveness of sins. Colossians 1:12-14.

All things:

Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ. Ephesians 5:20.

In everything:

In every thing give thanks: for this is the will of God in Christ Jesus concerning you. I Thessalonians 5:18.

Authorities:

I exhort therefore, that, first of all, supplications, prayers, intercessions, and giving of thanks, be made for all men; For kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty. For this is good and acceptable in the sight of God our Saviour. I Timothy 2:1-3.

His power and reign:

Saying, We give thee thanks, O LORD God Almighty, which art, and wast, and art to come; because thou hast taken to thee thy great power, and hast reigned Revelation 11:17.

Results in worship:

And when those beasts give glory and honour and thanks to him that sat on the throne, who liveth for ever and ever, The four and twenty elders fall down before him that sat on the throne, and worship him that liveth for ever and ever, and cast their crowns before the throne, saying, Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created. Revelation 4:9-11.

Other passages:

Psalm 105:1-3