John Calvin Commentary 1 Peter 4:19

"Wherefore let them also that suffer according to the will of God commit their souls in well-doing unto a faithful Creator." — 1 Peter 4:19 (ASV)

Wherefore let them that suffer. He draws this conclusion: persecutions should be endured submissively, because in persecution, the condition of the godly is much happier than that of the unbelieving who enjoy prosperity to their utmost wishes. However, he reminds us that we suffer nothing except by God's permission, which greatly comforts us. When he says, "Let them commit themselves to God," it is as if he had said, 'Let them deliver themselves and their life to God's safekeeping.' And he calls Him a faithful possessor, because He faithfully keeps and defends whatever is under His protection or power.

Some translate the word as “Creator”; and the term κτίστης means both. However, I prefer the former meaning, because by urging us to entrust our life to God, He makes Him its safekeeper. He adds, in well-doing, so that the faithful should not retaliate for the wrongs done to them, but should instead contend with the ungodly who injured them by well-doing.