Christian contentment, therefore, is the direct fruit of having no higher ambition than to belong to the Lord and to be totally at His disposal in the place He appoints, at the time He chooses, with the provision He is pleased to make.

It was with mature wisdom, then, that the young Robert Murray McCheyne wrote, ‘It has always been my aim, and it is my prayer, to have no plans with regard to myself.’ ‘How unusual!’ we say. Yes, but what people noticed about McCheyne was how content he was to pursue one driving ambition: to know Christ (Phil. 3:10). It is not accidental that when we make Christ our ambition we discover that He becomes our sufficiency and we learn contentment in all circumstances.

–In Christ Alone, by Sinclair B. Ferguson, pg. 190

Philippians 4:11-13 TNIV
I am not saying this because I am in need, for I have learned to be content whatever the circumstances. 12 I know what it is to be in need, and I know what it is to have plenty. I have learned the secret of being content in any and every situation, whether well fed or hungry, whether living in plenty or in want. 13 I can do all this through him who gives me strength.

I haven’t taken the time to put together a Thanksgiving post so I’ll provide a link to an article at Pulpit Magazine:
Contentment and Thanksgiving

John MacArthur at Pulpit Magazine is writing a series on Contentment based on Philippians 4:11-12.

In addition to that I’d like to mention that I always used to have Philippians 4:13 memorized without thinking about the context of the two verses before it.

Philippians 4:11-13
Not that I am referring to being in need; for I have learned to be content with whatever I have. I know what it is to have little, and I know what it is to have plenty. In any and all circumstances I have learned the secret of being well-fed and of going hungry, of having plenty and of being in need. I can do all things through him who strengthens me.

Jesus did say, “For truly I tell you, if you have faith the size of a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you.” (Matthew 17:20) But I think we need to keep Philippians 4:13 in context. All things is referring to being content in every condition of life. This includes being content in prosperity without being proud, greedy, hungering for more etc.

Then in 4:19 he says, “And my God will fully satisfy every need of yours according to his riches in glory in Christ Jesus.” (emphasis added) Our perception of our needs and what our needs really are may not line up. But He will supply our true needs and we can learn to be content in them through Him who gives us strength.