/services/data/v39.0/tooling/query?q=Select Id,ValidationName,Active,Description,EntityDefinition.DeveloperName,ErrorDisplayField, ErrorMessage From ValidationRule WHERE EntityDefinition.DeveloperName = 'Account'
/services/data/v39.0/tooling/query?q=Select Id,ValidationName,Active,Description,EntityDefinition.DeveloperName,ErrorDisplayField, ErrorMessage From ValidationRule WHERE EntityDefinition.DeveloperName = 'Account'