When buying a piece of land, it is more prudent to transact directly with the owner.
Why? Because you will be sure you are dealing with the right person, which is essential in every transaction.
But it may happen that the owner is either unavailable or unwilling to transact directly with you.
In such case, you will have to deal with him indirectly through his agent. Of course, this is if he has any.
But when buying a piece of land from an agent, you have to make sure that his authority to sell it for the owner is in writing.
Why? Because a sale of a piece of land through an agent is by law considered void if his authority to sell is not in writing.
By the use of the term void, it literally means having no legal force or effect.
Of course, this is the last thing you would ever want to happen if you are a buyer of a piece of land.
[References: Spouses Joselina Alcantara and Antonio Alcantara, and Spouses Josefino Rubi and Annie Distor-Rubi vs. Brigida L. Nido, as attorney-in-fact of Revelen N. Srivastava (G.R. No. 165133, April 19, 2010), Spouses Eliseo R. Bautista and Empera Triz C. Bautista vs. Spouses Mila Jalandoni and Antonio Jalandoni and Manila Credit Corporation (G.R. No. 171464, November 27, 2013)/ Manila Credit Corporation vs. Spouses Mila and Antonio Jalandoni, and Spouses Eliseo and Empera Triz Bautista (G.R. No. 199341, November 27, 2013), Articles 1874 and 1878 (5) of the Civil Code of the Philippines]