Seize the Initiative — ruling 1

A creature that gains first strike after other creatures with first strike or double strike deal combat damage in the first combat damage step will still deal damage in the second combat damage step.

Seize the Initiative : règles, fonctionnement et interactions (MTG)

Seize the Initiative is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Target creature gets +1/+1 and gains first strike until end of turn.

How it works : Seize the Initiative

Original English text — Wizards of the Coast / Scryfall

#1January 1, 2011· Wizards of the Coast
A creature that gains first strike after other creatures with first strike or double strike deal combat damage in the first combat damage step will still deal damage in the second combat damage step.
No other card is named in this ruling.