The phrase reminds us that our lives can be full of struggle and strain. We do have some influence over what we will struggle and strain over.
He Denied It and Said, “I Am Not” (John 18:25)
He had tried to serve Christ. He had failed. Jesus knew that he would. Jesus also knew that Peter would be restored.
God Working in Us (Hebrews 13: 20–21)
It is God who equips me to do the things that please him.