The genesis of thanksgiving is acknowledging that the source of all blessings is from God. We have received spiritual blessings (Ephesians 1:3). The fact that we were not worthy of these blessings makes us always remember His work on the cross. When we gather around His Table we express our gratitude to Him.
We have also received material blessings. David knew this truth when he said “Wealth and honor come from you; you are the ruler of all things. In your hands are strength and power to exalt and give strength to all (1 Chronicles 29:12). He is the creator of everything, and all blessings come from Him. If we are in need of money- He gives. If we need strength-He provides. If we are dishonored- He exalts us.
If we have received all these, then our thanksgiving must become thanks-living.