Off hand weapon property

[Hawkeye]

Out of fairness for a player in my group, I bring this to the experts. Only weapons that have the Off hand property can be used in the off hand, correct? You can't use, for example, two spears.

Hawkeye

 

[Mort_Q]

Correct. Although a PC can carry a spear in each hand, it offers no benefit. They can attack with one, or the other, but not both.

 

[Tai]

Unless you're a Two Weapon Ranger, of course. You can also gain the property from one weapon when you attack with the other one, as long as it doesn't specify "when you attack with this weapon" - this mainly applies to rods and wands and such, I think.

 

[abyssaldeath]

You can also gain the property from one weapon when you attack with the other one, as long as it doesn't specify "when you attack with this weapon" - this mainly applies to rods and wands and such, I think.

No you can't.

Weapon Properties
Many weapons have properties that provide a
constant benefit. To gain the benefit of a weapon’s
property, you must be wielding the weapon. Unless
specified otherwise, a property affects only the
weapon to which it’s attached.

 

[Tai]

Apologies, that was rather poorly worded. I'm referring to this entry from the Wizards FAQ:

3. If you wield a light shield, you can also hold an item as well, although you can’t attack with it. What if that item is an implement? Can you apply its implement bonus to your powers?

No. Using an implement to gain its bonuses is considered attacking with that implement. If you wield a light shield and hold an implement in the same hand, you would not get the implement enhancement bonus to your powers, but you would still benefit from any property that the implement has.​

Which says that you can use certain properties from a weapon you're not attacking with. This is covered in a bit more detail over here, but basically yes, you can't hold a flaming weapon in your off-hand and expect your main weapon to do fire damage. But you can, for example, hold a rod of corruption in your offhand and use its property when your pact boon triggers.