Martin Luther: History is like a drunk man on a horse. No sooner does he fall off on the left side, does he mount again and fall off on the right.

Here's a colorful saying attributed to Martin Luther:

“History,” Martin Luther said, “is like a drunk man on a horse. No sooner does he fall off on the left side, does he mount again and fall off on the right.” (source)

Documentation

Most often the quote is not documented. Curiously, an article found on the Christian History Institute website presented an entire article expounding what Luther meant, by taking a "closer look" at "both at Luther’s remarks and Luther himself".... without actually documenting the quote!

I'm not the first to come across this documentation problem. This old discussion post asks for help locating the source, and they actually arrived at the source: Luther's Table Talk.  The Table Talk is a collection of second-hand comments written down by Luther's friends and students, published after his death. Luther didn't write the Table Talk. Since the statements contained therein are purported to have been made by Luther, they should serve more as corroborating second-hand testimony to something Luther is certain to have written.

This particular second-hand comment was recorded by Veit Dietrich in 1533. There is no context surrounding the remark.  The German text can be found at WA Tr 1:298 (631). The text reads:

This text is included in LW 54:111. My electronic copy of LW 54 lists this Table Talk entry as 630.  This is an error: it's actually 631. 

Context 

No. 630: The World Is Like a Drunken Peasant
Fall, 1533

“The world is like a drunken peasant. If you lift him into the saddle on one side, he will fall off on the other side. One can’t help him, no matter how one tries. He wants to be the devil’s.” (LW 54:111)

Conclusion

There are various versions of this quote:

1800: Human reason is like a drunken man on horseback; set it up on one side, and it tumbles over on the other.

1952: Luther surely spoke very good sense when he compared humanity to a drunkard who, after falling off his horse on the right, falls off it next time on the left.

1992: Human nature is like a drunk peasant. Lift him into the saddle on one side, over he topples on the other side.

1993: Martin Luther said that humanity is like a drunk man on a horse. First he falls off on one side, then he climbs back up and falls off the other side.

2007: Martin Luther - an intemperate and hasty man, but far from a fool- once remarked that humanity is like a drunken peasant trying to ride a horse. We mount, fall off on one side, remount, and fall off on the other.

2014: Martin Luther said history is like a drunk man on a horse going from one ditch to the other, and it seems that is the case with us.

I'm sure many other examples of this quote are available. This is only a brief sampling. In the earliest version, it's "human reason" which is like a drunk person on horseback.  Then, it's humanity or "human nature." Finally, it's "history" which is like a drunk person on a horse.

According to the primary source, it's the "world."