1 Thessalonians 5:16

Rejoice evermore — In uninterrupted happiness in God. Pray without ceasing — Which is the fruit of always rejoicing in the Lord. In everything give thanks — Which is the fruit of both the former. This is Christian perfection. Farther than this we cannot go; and we need not stop short of it. Our Lord has purchased joy, as well as righteousness, for us. It is the very design of the gospel that, being saved from guilt, we should be happy in the love of Christ. Prayer may be said to be the breath of our spiritual life. He that lives cannot possibly cease breathing. So much as we really enjoy of the presence of God, so much prayer and praise do we offer up without ceasing; else our rejoicing is but delusion. Thanksgiving is inseparable from true prayer: it is almost essentially connected with it. He that always prays is ever giving praise, whether in ease or pain, both for prosperity and for the greatest adversity. He blesses God for all things, looks on them as coming from him, and receives them only for his sake; not choosing nor refusing, liking nor disliking, anything, but only as it is agreeable or disagreeable to his perfect will.