Haste is a beneficial (positive) status effect in Minecraft Java Edition 1.21.
minecraft:haste
Give Haste II for 60 seconds (Java Edition 1.13+; duration in seconds, then amplifier where 0 = level I):
Remove the effect from the nearest player:
Haste increases mining speed and attack speed by 10 percent per level, turning a good pickaxe into a block-shredding machine.
Haste comes only from beacons in survival: build a beacon on a mineral pyramid and select Haste as the primary effect. Haste II requires the full four-layer pyramid, which is the standard endgame mining setup.
Haste II plus an Efficiency V pickaxe mines stone instantly, which transforms terraforming and branch mining. Remember the attack-speed component too: Haste lets swords and axes swing faster, a small but real combat edge.
The effect ID for Haste is minecraft:haste. Java Edition 1.13+ /effect commands use this namespaced form. On Java 1.12.2 and earlier the numerical ID was 3.
Run /effect give @p minecraft:haste 60 1 to get Haste II for 60 seconds. The first number is the duration in seconds; the second is the amplifier (0 = level I, 1 = level II). Remove it with /effect clear @p minecraft:haste.
Haste is a beneficial (positive) status effect in Minecraft Java Edition, based on its registry category (beneficial).
From a beacon. Place a beacon on a pyramid of iron, gold, diamond, emerald, or netherite blocks and choose Haste; a full four-layer pyramid unlocks Haste II. There is no Haste potion in survival.
Yes, 10 percent faster mining per level, and it also speeds up attack swings by 10 percent per level. Haste II with an Efficiency V pickaxe is fast enough to insta-mine stone.