Mix 3 drops liquid dish soap with 1 cup lukewarm water. Mix until the water is sudsy.
Dip a toothbrush into the soapy water, and scrub the glue stain with the toothbrush. If the glue is water soluble, scrubbing with the toothbrush might remove the glue completely.
Wipe the area with a cloth.
If the toothbrush didn't remove all the glue, dab acetone directly on the glue. This will be necessary if the glue is epoxy or if it is very strong and durable.
Rinse the marble surface immediately to remove any traces of liquid dish soap or acetone. Wipe the area dry to prevent water marks from developing.