what is your goal?
- to start slider with a active class around a image?
- add active class based on what image is shown?
first should be possible with php without big problems. use something like that:
<div class="quote-section">
<div class="slider4">
<?php if( have_rows('quote_slider') ):
$img_count=1;
while ( have_rows('quote_slider') ) : the_row();
if ($img_count == 1) {
?>
<li class="slide active">
<div class="quote"><?php the_sub_field('quote'); ?></div>
<div class="name"><?php the_sub_field('name'); ?></div>
<div class="image"><img src="<?php the_sub_field('image'); ?>" /></div>
</li>
<?php } else {?>
<li class="slide">
<div class="quote"><?php the_sub_field('quote'); ?></div>
<div class="name"><?php the_sub_field('name'); ?></div>
<div class="image"><img src="<?php the_sub_field('image'); ?>" /></div>
</li>
<?php }
$img_count++; ?>
<?php endwhile;
else : endif; ?>
</div>
</div>
second is/shouldbe part of your slider js, and there i could not help you
