The word thanksgiving seems like such a natural part of our praise to God that you might be surprised that it's missing from the earliest parts of the Old Testament. Why is this? You'll find the answer in baker's theological dictionary:
The Old Testament. Early in the Old Testament both the language and the concept of thanksgiving are conspicuous by their absence. The Old Testament lacks an independent vocabulary of thanksgiving or gratitude; it uses the verb yada [h'd"y], and the cognate noun toda [h'd/t], both ordinarily translated as "praise, " to convey the concept. Even the concept is rare in the Pentateuch. Neither Adam nor Eve thanked God for his creation, and, compared to Abel's gift of the fat portions from the firstborn of his flock, Cain's gift of "some fruit" seems singularly thankless. The families of Isaac and Jacob contended over God's blessing rather than thanking him for it. Ingratitude reached its nadir when, after the exodus, Israel grumbled again and again, rather than thanking God for his deliverance and for food that literally fell from heaven.
Perhaps the laws for thank offerings should be seen against Israel's failures to that point. The thank offering was one type of peace or fellowship offering within the sacrificial system of the Mosaic covenant. Distinct from the sin and guilt offerings, they were a subcategory of peace offering, ordained to express gratitude to the Lord for any deliverance, any act of love (Leviticus 7:11 ; Psalms 107:21). Even apart from the sacrificial system or the terminology of thanksgiving, wisdom literature encourages gratitude for God's material provision and exposes the folly of greed (Psalms 104:15 ; Ecclesiastes 5:8).
Thanksgiving is more common in the psalms. About twenty psalms command or invite Israel to sing songs of thanksgiving. "Give thanks to the Lord, for he is good" is a common refrain (Psalms 106:1 ; Psalms 118:1 ; Psalms 136:1). Some psalms specify a reason, linking thanksgiving with Acts of love and worship, exhorting worshipers to glorify God with thanksgiving (Psalms 69:30), come before him with thanksgiving (Psalms 95:2), enter his gates with thanksgiving (Psalms 100:4), sing to the Lord with thanksgiving (Psalms 147:7). Perhaps surprisingly, many cries for aid and laments conclude with thanksgiving (individual cries for help in Psalms 7:17 ; Psalms 28:7 ; Psalms 35:18 ; Psalms 52:9 ; Psalms 54:6 ; Psalms 86:12 ; communal cries in Psalms 79:13 ; Psalms 106:47).
Discover more about thanksgiving in the Bible as you continue to read this excellent resource.