17 Because God wanted to make the unchanging nature of his purpose very clear to the heirs of what was promised, he confirmed it with an oath. (Hebrews 6:17 NIV)
Little in our lives is unchanging. However, we can rely upon God to be unchanging and to work out for us whatever circumstance we happen to find ourselves in. This may not mean that things get easy, but that they work to His purpose.
Ultimately, He is working us toward having a similar unchanging nature as much as that is possible in this world.