All creatures lose all abilities and have base power and toughness 1/1.
This is the current interaction between Humility and Opalescence: The type-changing effect applies at layer 4, but the rest happens in the applicable layers. The rest of it will apply even if the permanent loses its ability before it's finished applying. So if Opalescence, Humility, and Worship are on the battlefield and Opalescence entered before Humility, the following is true: Layer 4: Humility and Worship each become creatures that are still enchantments. (Opalescence). Layer 6: Humility and Worship each lose their abilities. (Humility) Layer 7b: Humility becomes 4/4 and Worship becomes 4/4. (Opalescence). Humility becomes 1/1 and Worship becomes 1/1 (Humility). But if Humility entered before Opalescence, the following is true: Layer 4: Humility and Worship each become creatures that are still enchantments (Opalescence). Layer 6: Humility and Worship each lose their abilities (Humility). Layer 7b: Humility becomes 1/1 and Worship becomes 1/1 (Humility). Humility becomes 4/4 and Worship becomes 4/4 (Opalescence).