walk softly and carry a big stick

To walk softly and carry a big stick is an older proverb which means to be advising the tactic of caution and non-aggression or non aggressive behavior and to be backed up the ability to do violence should it be required. This phrase means that you should walk softly and practice caution so that you could hopefully get through some sort of dilemma without using aggressive behavior, but also be prepared if you do need to take action.