Flame Slash 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

Flame Slash deals 4 damage to target creature.

How it works : Flame Slash

Original English text — Wizards of the Coast / Scryfall

No additional ruling has been published for this card.

Interactions with other cards

These cards' text mentions Flame Slash.

Heartflame Duelist // Heartflame Slash

Instant and sorcery spells you control have lifelink. Heartflame Slash deals 3 damage to any target. (Then exile this card. You may cast the creature later from exile.)