Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +3/+3 and has reach.
Channel — {1}{G}, Discard Favor of Jukai: Target creature gets +3/+3 and gains reach until end of turn.
Discarding the card is part of the cost to activate a channel ability.
If a channel ability requires a target, you may not activate it without a target just to discard the card.