Learn Farsi: تو امروز پیشم آمدی؛ باید این لطف را جبران کنم. - You came to me today; I must make up for this favor.

The word پیش (pish) literally means "front" or "presence," but it is often used as a preposition meaning "to" or "with" when referring to a person. As you are learning in this lesson, you can attach pronominal enclitics (personal endings) directly to prepositions. Here, the ـم (-am) ending means "me" or "my". Put together, پیشم (pish-am) means "to my presence" or simply "to me."

Can I use پیش anytime I want to say I am going "to" somewhere?

No, پیش (pish) is used for "to" only when your destination is a person. Because the sentence says "came to me", you use پیشم. If you were talking about going to a physical place, like a house or a city, you would use the preposition به (be) instead.

Why is the verb جبران کنم in this form instead of the present tense جبران می‌کنم?

The word باید (bâyad), meaning "must" or "should," requires the verb that follows it to be in the subjunctive mood. For the compound verb جبران کردن (jobrân kardan, meaning "to make up for" or "to compensate"), forming the subjunctive means you do not use the می‌ prefix, leaving us with just جبران کنم (jobrân konam) for the "I" form.

Why do we need را right after این لطف?

را (râ) is the marker that points out a specific direct object in a sentence. The action is making up for something, and the thing being made up for is (). Because adding "this" makes the favor specific and definite, you must put immediately after it.