The European Central Bank shocked the world and caused a global sell-off when it announced a smaller-than-expected stimulus package this week. The message from ECB President Mario Draghi sent the euro surging more than 3 percent against the dollar, seeing its best one-day gain in more than five years, a feat that left veteran trader and commodities king Dennis Gartman stunned.

"This is something more than a bounce," Gartman told CNBC's "Futures Now" on Thursday. "I've been trading for 40 years, and anytime you see a four euro move, you have to stand back in absolute awe and in the majesty of that move. It is stunning."

Gartman noted that magnitude of the move was caused by Draghi's hawkish tone. "The ECB caught everyone off guard" by not enhancing the amount of its monthly purchase, he said.

Read More ECB hawks win, and Janet Yellen should be happy

The euro zone's currency has been in a precipitous decline all year, as the rally has crushed global currencies and commodities alike. The euro is down more than 9 percent versus the dollar in 2015.

According to Gartman, the event could be a foreshadowing of the tone that Federal Reserve Chair Janet Yellen will take at the next FOMC meeting in two weeks. "There's no doubt she's going to raise," he said. "But the question is how aggressive she will be at the turn of the year." For him, instead of worrying about the first rate hike, investors should take note of how quickly the following one comes.

Read MoreCould the ECB decision actually be GOOD for markets?

Over the next few sessions, Gartman expects the dollar to continue to weaken, which will bode well for the beaten commodities space. "The first thing that's going to happen is the commodities market is going to turn much higher," said the editor and publisher of The Gartman Letter. He pointed to the Thursday surge in gold, crude and wheat as examples.

"This is a big turning point for the currency and the commodity markets," Gartman said. "If you can buy grains, and cotton lower you probably should," he said. "What you saw Thursday is probably supportive of gold for the next few months."