Depending upon the the translation, some form of the word “thank” can be found in the Bible between 130 and 210 times. So it is fair to say the Bible has much to say about giving thanks and of the many reasons to give thanks.
Leviticus is largely about the ceremony involved in sacrifices, and it talks about attitude as well as procedure, substance as well as form.
Leviticus 22:29 Authorized (King James) Version (AKJV)
29 And when ye will offer a sacrifice of thanksgiving unto the Lord, offer it at your own will.
Thanks requires thankfulness. King David was a thankful man. Thus, he wrote many psalms expressing his thanks. One ends with these words.
2 Samuel 22:50-51 Authorized (King James) Version (AKJV)
50 Therefore I will give thanks unto thee, O Lord, among the heathen,
and I will sing praises unto thy name.
51 He is the tower of salvation for his king:
and sheweth mercy to his anointed,
unto David, and to his seed for evermore.
King David, a great king, saw God as a merciful, loving, and unfailing protector.
Imagine the Jews returning to Jerusalem after their long Babylonian captivity. They gave thanks to the Lord for His forgiveness and for allowing them to lay a new foundation.
Ezra 3:11 Authorized (King James) Version (AKJV)
11 And they sang together by course in praising and giving thanks unto the Lord; because he is good, for his mercy endureth for ever toward Israel. And all the people shouted with a great shout, when they praised the Lord, because the foundation of the house of the Lord was laid.
Daniel was one of those exiles, although it is not likely that he ever returned to his native land. Even as a high Persian official he endured threats to his life. What happened when the king he served, Darius, issued a decree against praying to any god except himself?
Daniel 6:10 Authorized (King James) Version (AKJV)
10 Now when Daniel knew that the writing was signed, he went into his house; and his windows being open in his chamber toward Jerusalem, he kneeled upon his knees three times a day, and prayed, and gave thanks before his God, as he did aforetime.
Trusting in the Lord, Daniel ignored the decree and continued to give thanks. To those who love Him, the Lord will give cause for thanks. So it has always been for the remnant of Zion.
Isaiah 51:3 Authorized (King James) Version (AKJV)
3 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.
Those who give thanks in pride, however, find their prayers unwelcomed by God.
Luke 18:11 Authorized (King James) Version (AKJV)
11 The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican.
That Pharisee prayed with himself, not to God. Instead of extolling our own virtues, we give thanks to God for the virtues of others.
2 Thessalonians 1:3 Authorized (King James) Version (AKJV)
3 We are bound to thank God always for you, brethren, as it is meet, because that your faith groweth exceedingly, and the charity of every one of you all toward each other aboundeth;
We give thanks as our Lord did, in humility.
Mark 14:22-25 Authorized (King James) Version (AKJV)
22 And as they did eat, Jesus took bread, and blessed, and brake it, and gave to them, and said, Take, eat: this is my body. 23 And he took the cup, and when he had given thanks, he gave it to them: and they all drank of it. 24 And he said unto them, This is my blood of the new testament, which is shed for many. 25 Verily I say unto you, I will drink no more of the fruit of the vine, until that day that I drink it new in the kingdom of God.
Jesus, humbling Himself in obedience to the Father, gave thanks for the bread and the wine. Then He celebrated the sacrifice He would make on our behalf so that we might not know the second death.
1 Corinthians 15:50-58 Authorized (King James) Version (AKJV)
50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption. 51 Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed, 52 in a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed. 53 For this corruptible must put on incorruption, and this mortal must put on immortality. 54 So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory. 55 O death, where is thy sting? O grave, where is thy victory? 56 The sting of death is sin; and the strength of sin is the law. 57 But thanks be to God, which giveth us the victory through our Lord Jesus Christ. 58 Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.
So it is that today we continue a tradition, thankful for the opportunity to live in a land founded by a great many thankful pilgrims, pilgrims thankful for the providence, the mercy, the grace, and the love of our Creator.