Immutability
Staci Eastin (Writing and Living) recently wrote a series of posts on the unchangeableness of God, listing and explaining reasons why it’s important to understand this doctrine.
And Diane Bucknell posted a collection of quotes and scripture on the immutability of God (Theology for Girls).
Goodness
God’s goodness is our comfort (Kim Shay at Out of the Ordinary).
Self-Existence, Immutability, Goodness, and More
What is God?, Questions 2 of the New City Catechism, including video commentary by D. A. Carson. You’ll want to check out the other questions in the catechism, too.