For using the Jetpack Twitter widget in a template, as of Jetpack 2.2.2

Jetpack Twitter widget template tag example.php

  the_widget( 'Jetpack_Widget_Twitter',
    array(
      'title' => 'RNS on Twitter',
      'account' => 'RNS',
      'show' => 3,
      'hidereplies' => true,
      'hidepublicized' => true,
      'includeretweets' => true,
      'followbutton' => true
    ),
    array(
      'before_widget' => '<aside class="widget widget_twitter">',
      'before_title' => '<h1 class="widget-title">',
      'after_title' => '</h1>',
      'after_widget' => '</aside>',
    )
  );