I am preaching on Mary and Martha in Luke 10:38-42 this weekend, God-willing.
Such a simple message, but so easy to lose track of.
Christ is the foundation. Christ's service to us is needful - our service to him is derivative from that. Christ must be all, otherwise we'll go astray. You can serve Christ and get exhausted, and have made the wrong choice in doing it, unless you prioritise sitting at his feet and letting him minister to you. It's not what we do for Christ - it's what Christ has done and is doing in us.