1 Unless the Lord builds the house,
    the builders labor in vain.
Unless the Lord watches over the city,
    the guards stand watch in vain.
 

2 In vain you rise early
    and stay up late,
toiling for food to eat—
    for he grants sleep to those he loves.

3 Children are a heritage from the Lord,
    offspring a reward from him.
 

4 Like arrows in the hands of a warrior
    are children born in one’s youth.
 

5 Blessed is the man
    whose quiver is full of them.
They will not be put to shame
    when they contend with their opponents in court.

Why do you do what you do? Think about everything that consumes your calendar in a given week. What is your motive for each task or commitment? What is your strength for each activity?

Any work that you do, no matter how "good", must be done for and through and with the Lord. 1 Corinthians 13: 1-4 speaks to this; you could give all your possessions to the poor and even give up your life, but unless you do it with love, it profits you nothing. Motive matters. Indeed, this was Jesus' frustration with the Pharisees. They did the right things. Their behavior was correct. Their heart was not. We can change our behavior. Only God can change our heart. 

What is your motive for what you do? It is healthy to examine. Do you attend that group because it is a part of your weekly routine, or because you yearn to grow closer to Jesus and to help others do the same? Do you volunteer because it's what you should do or do you go with Jesus' heart to love and serve?

And for all you do, God must be your strength. Jesus says in John 15:5 that apart from Him we can do nothing. Psalm 33:16-17 and Hosea 14:6 similarly affirm that none  of our efforts are sufficient. No matter how hard we work, without the Lord it all profits nothing. With the Lord, when you've done what He calls you to do, you can rest, knowing you're approved by Him, not approved for the success of your effort. So rest, daughter/son of God, knowing you are cherished by your Father.