Romans 1:21, 22 Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. 22 Professing themselves to be wise, they became fools.
2 Timothy 3:1-2 This know also, that in the last days perilous times shall come. 2 For men shall be lovers of their own selves, covetous, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy.
The giving of thanks or a thankful heart is an important part of the Christian life. To the Christian, every day ‑ as well as our prayer life ‑ should be filled with thanksgiving (Philippians 4:6). Life has a dark side and a bright side, but we will see exactly what we train ourselves to see. Our outlook on life is entirely dependent on our inner attitude, and thanksgiving keeps our attitude focused on the right things. On the other hand, ingratitude could be said to be one of the greatest sins of mankind. It is a sign of a foolish heart, it puts out the light of God in our life (Romans 1:21) and is a prominent sign of the last days (2 Timothy 3:1, 2). It is a part of what corrupted the heart of the ancient world beyond the point of Divine remedy (Romans 1:18-32).
The unthankful are actually fulfilling Bible prophecy about the last days. Romans 12:2 instructs us, “And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.” Let’s be nonconformists and rebel against this unthankful spirit of the last days and renew our mind to giving thanks always for all things unto God (Ephesians 5:20).