Summary: Elusive as a will 'o the wisp, contentment is the heritage of God's people. Paul provides practical instruction for believers to find contentment in their service to Christ.
“I rejoiced in the Lord greatly that now at length you have revived your concern for me. You were indeed concerned for me, but you had no opportunity. Not that I am speaking of being in need, for I have learned in whatever situation I am to be content. I know how to be brought low, and I know how to abound. In any and every circumstance, I have learned the secret of facing plenty and hunger, abundance and need. I can do all things through him who strengthens me.
“Yet it was kind of you to share my trouble. And you Philippians yourselves know that in the beginning of the gospel, when I left Macedonia, no church entered into partnership with me in giving and receiving, except you only. Even in Thessalonica you sent me help for my needs once and again. Not that I seek the gift, but I seek the fruit that increases to your credit. I have received full payment, and more. I am well supplied, having received from Epaphroditus the gifts you sent, a fragrant offering, a sacrifice acceptable and pleasing to God. And my God will supply every need of yours according to his riches in glory in Christ Jesus. To our God and Father be glory forever and ever. Amen.” 
It is easier to be a Christian at some times than at others. At least most of us appear to think that to be true. When life is going well, when there is no illness in our family, when difficulties are absent and when all our debts are paid and we have sufficient income to secure those things necessary to insure a comfortable life, surely it is easier to profess the Faith of Christ than when these things are not true. Prolonged illness, unjust persecution, marital stress, crushing financial obligations—each takes a toll on the vibrancy of our Christian life and testimony. But is it easier to be a Christian when everything is going well then when life turns sour? I am not so certain that such is true. Let's explore the issue together.
In the days immediately preceding his death, Moses recited a song for Israel. What I find interesting is that in the midst of that song Moses included some sobering words for all who worship the Living God, especially when life is going well.
“Jeshurun grew fat, and kicked;
you grew fat, stout and sleek;
then he forsook God who made him
and scoffed at the Rock of his salvation.”
When Israel was blessed, they turned from God. Wandering in the wilderness—committed to God. Fighting for survival—committed to God. Prosperity—not so much.
Far more of us suffer injury resulting from prosperity then are ever destroyed by poverty. Poverty, whether poverty of soul or poverty of possessions, forces one to resort to the Lord. We know what it is to be in need; and when difficulties do come, we immediately run to the Lord. However, sufficiency seems somehow to cause us to imagine that we have no need for the Lord. In times of prosperity we imagine that we are able in our own strength to care for our needs.
A famous U. S. labour leader, engaged in prolonged contract negotiations, was asked what would make him satisfied. His reply was revealing—given, in fact, for the whole of the race, I suspect—he answered, “A little more.” His answer echoed that which Oliver Wendell Holmes wrote concerning contentment: