The question should be: 'What is the difference between 'holding' and 'held' in the following sentence?' 'Stop holding on'. This is the gerund form (..ing) . We use the gerund form after many verbs, including 'stop'. 'Stop holding on' means 'Don't hold on any more.' 'Just be held'. This is the past participle form (held), used because it is a passive construction. Someone else is holding this person, and the speaker is telling the person to let this happen, to allow himself/herself to be held.