Why do some people burn candles to pray. Is it necessary to burn candles and pray? God looks at the heart right?

Candles are one of the important sacramentals used in the Catholic Church since it assists the liturgy of the Sacraments. Catholics also use candles while offering prayers. These are called ‘votive candles’. Candles are an external expression of prayer. Just as a candle, our prayers too are continually offered up to God.

Different types of candles are used to signify the solemnity of different liturgy. Candle used in the liturgy of Mass signifies the presence of the risen Christ. Similarly there are many other special candles, baptismal candle, paschal candle of Easter vigil etc, to mention a few. 

It’s not necessary or even required to light a candle while praying. It’s the internal dispositions that matters in prayer. Lighting candles is just one of an outward expression of our internal dispositions. A mere outward expression without an internal disposition will not add any merit to our prayers.  But a sincere heart, along with an external symbol like a burning candle can make our prayers really meaningful.