Work won’t save us; grace saves us to work.
Anyway, that is how I see it. Slave, servant, brother or friend all labor in service to their Lord and King. We are meant to be fruitful glorifying our Father. Jesus explained how this WORK is accomplished. “Jesus answered and said to them, “This is the work of God, that you believe in Him whom He has sent.” (John 6:29 NASB) Now, the biggest part of believing in someone is believing that what they say is true.
“I am the true vine, and My Father is the vinedresser. Every branch in Me that does not bear fruit, He takes away; and every branch that bears fruit, He (cleans) prunes it so that it may bear more fruit. You are already (pruned like a branch) clean because of the word which I have spoken to you.
Remain in Me, and I in you. Just as the branch cannot bear fruit of (from) itself but must remain in the vine, so neither can you unless you remain in Me. I am the vine, you are the branches; the one who remains in Me, and I in him bears much fruit, for apart from Me you can do nothing.
If anyone does not remain in Me, he is thrown away like a branch and dries up; and they gather them and throw them into the fire, and they are burned. If you remain in Me, and My words remain in you, ask whatever you wish, and it will be done for you. My Father is glorified by this, that you bear much fruit, and so prove to be My disciples.
Just as the Father has loved Me, I also have loved you; remain in My love. If you keep My commandments, you will remain in My love; just as I have kept My Father’s commandments and remain in His love. These things I have spoken to you so that My joy may be in you, and that your joy may be made full.” (John 15:1-11 NASB)