Rule 509.2 · Declare Blockers Step

Second, the active player gets priority. (See rule 117, “Timing and Priority.”)

Subrules

Any abilities that triggered on blockers being declared or that triggered during the process described in rule 509.1 are put onto the stack before the active player gets priority; the order in which they triggered doesn’t matter. (See rule 603, “Handling Triggered Abilities.”)

Other rules in this chapter

Ask the judge Pro

The life counter has an AI judge that answers your play citing the exact rules. It is part of Gatewatch Pro; the rules, Oracle text and rulings stay free.