When my son’s teacher asked me to serve as a chaperone for their science camp, I hesitated. How could I be a role model when mistakes littered my past, when I still struggled, stumbled, and slipped into old bad habits? God helped me love and raise my son, but I often doubted He could use me to serve others.

Sometimes I still fail to recognize that God—the only perfect One, the only One who can change hearts and lives—transforms us over time. Then the Holy Spirit reminds me how Paul encouraged Timothy to embrace his on-the-job training, persevere in faith, and…