Haste

Haste is a static ability that lets a creature ignore summoning sickness. The creature is able to attack without waiting for one turn and use its activated abilities.

Comprehensive Rules
702.10. Haste

702.10a Haste is a static ability.

702.10b If a creature has haste, it can attack even if it hasn’t been controlled by its controller continuously since his or her most recent turn began. (See rule 302.6.)

702.10c If a creature has haste, its controller can activate its activated abilities whose cost includes the tap symbol or the untap symbol even if that creature hasn’t been controlled by that player continuously since his or her most recent turn began. (See rule 302.6.)

702.10d Multiple instances of haste on the same creature are redundant.