A condition is something that creates or extinguishes a duty.
A condition precedent is a condition which must occur or be performed before some right dependent on it accrues, or some act dependent on it, is performed. Conditions concurrent are those which are mutually dependent and must be performed at the same time. A condition subsequent is a condition referring to a future event; upon the occurrence of the condition, the obligation is no longer binding upon the other party.
Before any party to a contract can require the other party to perform any act under it, the party must perform all conditions precedent imposed upon the party and must be able and shall offer to fulfill all conditions concurrent imposed upon the party on the fulfillment of all conditions concurrent imposed upon the other party.
If a party is not in default, performance of a condition precedent or condition concurrent imposed is excused if the other party refuses to perform their own promises and does not retract such refusal before the time at which performance is due.