I have been meditating on what it means to be “established with grace.“
The particular text of interest is, “Be not carried about with divers and strange doctrines. For it is a good thing that the heart be established with grace; not 
with meats, which have not profited them that have been occupied therein.” (He 13:9) There are many other great verses which might also be helpful here.
What is grace? What does it mean to be established with something? How can we live this out in God? What does it look like, and how do we get there?
My thought: being established with grace is more than knowing God’s love and forgiveness, more than resting in Christ’s unconditional acceptance; it is having supernatural confidence that God is transforming me into the image of Christ, creating His likeness in me, enabling me to love and obey Him. (2Co 9:8) Through the power of the Holy Spirit I access grace by faith … that is, I rest in Christ’s utter sufficiency and faithfulness, delighting in Him, being filled with all joy and peace in believing, abounding in hope. (Ro 15:13)