The Bible does not order or forbid lighting a candle, except for idolatry or witchcraft, when it is a sin. Sailing has no special power. Using candles for lighting or decoration is not a sin.
In the Bible, some concepts are illustrated with candles or fire. In the Old Testament, candles and lamps were lit before God in the tabernacle and, later, in the temple ( Leviticus 24: 3-4 ). The light represented the way God illuminates life, reveals hidden things and knows the intentions of the heart. The power was not in the candles; it is in God.
When Jesus came, he declared that he is the light of the world. All Old Testament symbols pointed to Jesus. Now the true light had come ( John 1: 3-5 ). Symbols, like candles, are no longer needed.
Light candle and prayer
The practice of lighting a candle to pray is not in the Bible. The first disciples did not light candles for this purpose. Candles were used only for lighting, because there was no electric light. They were not used to help with prayer.
Lighting a candle gives no power to prayer. A prayer with a lighted candle is the same as a prayer without a candle for God. He is not pleased with candles, but with a contrite and humble heart. We don’t need to make sacrifices, buying candles to win God’s favor ( Psalm 51: 16-17 ).
Read here: does prayer have power? What is the power of prayer?
In some cases, the candle can help to remember that Jesus is our light and that he must be the center of our lives, or that we are called to be light to the world. But this symbol is neither necessary nor required in the Bible.
Light a candle for saints or for the dead
The dead don’t need a candle. They are dead, their fate is already sealed and there is nothing that we alive can do to change their situation. The dead also cannot communicate with us or help us, and a candle is not going to change that. Lighting a candle for the dead is not biblical.
Look here: what does the Bible say about talking to the dead?
The saints cannot help us either. And even if they could, their prayers could not be bought with candles. We have only one intercessor with God and we don’t need any more – Jesus ( 1 Timothy 2: 5 ). We can place our orders directly with Jesus, without intermediaries, like saints or candles.
Jesus loves us and is already giving attention to each one of us ( Matthew 10:30 ); we don’t need to do much to get His attention and favor! Lighting a candle to ask for help from the saints or the dead is a lack of faith in God and His love for us. In many cases, lighting a candle even becomes idolatry, because the saint (or even the candle) receives the glory that only God deserves.
See also: is it biblical to worship Mary and the saints?
Light candle as decoration
The act of lighting a candle in itself is not sinful. There is nothing wrong with liking the smell or light of a candle. The believer is free to light a candle if he wishes ( Romans 14:22 ).
The most important is the heart. If lighting a candle makes you uncomfortable or tempting you to idolize, then don’t use candles. But, if your conscience allows it, you can use it.