Remember, Big J has absolutely no qualms against beating the shit out of people who disrespects his dad's house.
I feel like that particular section in the Bible is similar to the east-Asian idiom “Even the Buddha will get mad, if you slap him three times in the face.” I.e. even the patience of a saint can be understandably lost in the right circumstance.
It's important to also note that Big J made himself a whip, BY HAND, which would have taken him HOURS, if not straight up all day.
He just stood there, menacingly, forging the instrument of his wrath
Making a whip is easy. You put something mildly heavy on the end of a rope, and that's a whip...technically, a very long morningstar. And the passage actually tells you what type of whip it is.
"And when he had made a scourge of small cords, he drove them all out of the temple, and the sheep, and the oxen; and poured out the changers' money, and overthrew the tables;" -John 2:15
Most likely, it's something similar to cat o' nine tails which is basically just few strands of short rope tied together, which can be put together under 5 minutes.