The damage is still dealt fully, even though [[Worship]] makes it so your life total can't go under 1. This means you gain the full 4 life from the lifelink creature.

Source: Gatherer rulings


> 10/4/2004	It reduces your life total to 1, not the damage to 1.    
> 10/4/2004	Worship does not prevent damage. It causes some damage to be
> unable to lower your life total. So any damage rendered useless by
> Worship was still dealt and is counted by effects that track the
> amount of damage done to a player. In addition, Worship does not
> prevent loss of life, so loss of life bypasses Worship.