“And you shall come and you shall bring all your burnt offerings there… your offerings of avowal and your voluntary offerings’”
It is a positive commandment that anyone who avows or pledges any type of offering for the altar or anything for the yearly upkeep of the House (Beis Hamikdash), should bring it at the first possible festival after his avowal as it says “and you shall come there and you shall bring your burnt offerings there…. And your avowals.” Chazal have explained the phrase “and your avowals” as a referring to a promise, that is to say, that a person obligates himself by saying “I take upon myself to bring an offering”. “Your pledges” refers to a free gift like one who sanctifies a specific animal and says “this is a burnt offering”. Chazal have explained from the expression “and you shall come there and you shall bring them there,” that the verse comes to establish them as an obligation, that a person is obligated to bring them at the first festival.
Amongst the roots of the commandment: it is not fitting for a person to be lazy with regards to vows that he has made to fulfil a commandment. In any case, The Torah will not compel him to go up immediately lest people refrain from vows and pledges. But on a festival where they have to go up to the temple anyway, the Torah warns them to pay their avowals.
This commandment applies at the time when the temple exists, for then we have the option of offering avowals and pledges and we have a place to offer them, but nowadays Chazal say we do not sanctify sacrifices at all, and even one who transgressed and sanctified does not have the possibility to bring it to the Sanctuary because the temple has been destroyed through our sins.