Now may our Lord Jesus Christ himself and God our Father, who loved us and through grace gave us eternal comfort and good hope, comfort your hearts and strengthen them in every good work and word.
(Church in Wales Lectionary, New Revised Standard Version)
When we make telephone calls to loved ones we often wrap up what has been said by wishing that whatever plans they have talked about or any concerns they have will work out. You know the kind of thing - "I hope Aunty gets better", or "Take care on the road when you go out today!" The writer of 2 Thessalonians (and there is some disagreement over whether it was Paul who wrote this letter), begins to wrap up his words in a prayer. There are a number of other such prayers among these New Testament epistles (letters), and those who lead prayers in worship often use them.
Paul reminds his readers what God has already done for them - He has loved them! Their Heavenly Father has always been there and because of this they know that He will be there in the future. This should give them considerable comfort that He will help them once again out of the goodness of His heart, and give them the strength to work and speak for Him.
Notice the final order - we are to do good work first, before telling others about God though we should do both.
Lord Jesus Christ,
comfort us this day
and give us hope
as we complete the tasks
You have given us to do.
May we remember all You
have done in the past,
and ask Your help
with the tasks of this day
as well as those whom we meet.
Amen.
You might like to look up these prayers found among the New Testament Epistles: