Why do Catholics pray to Saints?

To pray is to ask. Intercession is asking on the behalf of another. Saints are those who are holy. With the proper understanding of prayer, intercession, and saints, asking the saints in heaven to intercede for us is obvious.

Jesus is the one intercessor to the Father for all (1), and the Holy Spirit intercedes for us. (2) We also know we are called to pray for one another. (3) The subject for all of this seems to be to God and not saints. Although, when Jesus healed the paralytic, he healed him when he saw the faith of his friends. (4) This powerful story shows Jesus honors the intercession of our friends.

The power of God and the intercession of Christians recognize no boundaries. (5) Those in Heaven can pray for us just like those on Earth. We know this truth as it was revealed to John on Patmos, in that the prayers of the saints were presented to Jesus in golden bowls in the form of incense. (6) When a Christian wants to have someone pray for them, they know, that the prayers of the holy have great power (7).

Citations: (1) 1 Timothy 2:5-8, (2) Romans 8:26-27, (3) 1 Thessalonians 5:25, (4) Mark 2:1-5, (5) ccc 2636, (6) Revelations 5:8, (7) James 5:15-16