“Give thanks in all circumstances! [1 Thessalonians 5:18]
“Thankfulness ought always to characterize the people of God, as they say to themselves: ‘Praise the Lord, O my soul, and forget not all his benefits’ (Ps.103:2). Indeed, ‘the Christian’s life is to be an unceasing eucharist’. Thanksgiving also belongs, side by side with rejoicing and praying, to our public worship (Cf. Eph.5:20). In it there is a place for a ‘general thanksgiving’ in which we express our gratitude both for the material blessings of the creation and above all for God’s priceless love in redeeming the world through Jesus Christ, which we celebrate at the Lord’s Supper, the Holy Communion or, as it soon became to be called in the early Church, the Eucharist (*eucharistia* meaning simply thanksgiving’)….
“We cannot of course thank God ‘for all circumstances’, including those which are evil and displeasing to him; but we can and should thank him *in all circumstances* or ‘whatever happens’ (REB). We may not always feel like praising, praying or giving God thanks. Our circumstances may not be conducive to these things. Yet we are to do so all the same. Why? Because *this is God’s will for you in Christ Jesus* (18b). This statement almost certainly belongs to all three commands which precede it. It is God’s will, as expressed and seen in Jesus Christ, whenever his people meet together for worship, and whatever their feelings and circumstances may be, that there should be rejoicing in him, praying to him and giving him thanks for his mercies.”
From: John Stott, The Message of Thessalonians: The Cross of Christ. The Bible Speaks Today, Inter-Varsity Press UK, Nottingham.