Sorrow's Path

This has two abilities. The second ability triggers any time it becomes tapped, whether to pay for its ability or not.

When Sorrow’s Path’s first ability is activated, its second ability triggers and goes on the stack on top of the first ability. The second ability resolves first, and may cause some of the attacking creatures to be dealt lethal damage.

Abilities that trigger whenever one of the targeted creatures blocks will trigger when the first ability resolves, because those creatures will change from not blocking (since they’re removed from combat) to blocking. It doesn’t matter if those abilities triggered when those creatures blocked the first time. Abilities that trigger whenever one of the attacking creatures becomes blocked will not trigger again, because they never stopped being blocked creatures. Abilities that trigger whenever a creature blocks one of the attacking creatures will trigger again, though; those kinds of abilities trigger once for each creature that blocks.