WLC Q.179: Are we to pray unto God only?
God only being able to search the hearts, (1 Kings 8:39, Acts 1:24, Rom. 8:27) hear the requests, (Ps. 65:2) pardon the sins, (Micah 7:18) and fulfill the desires of all; (Ps. 145:18) and only to be believed in, (Rom. 10:14) and worshipped with religious worship; (Matt. 4:10) prayer, which is a special part thereof, (1 Cor. 1:2) is to be made by all to him alone, (Ps. 50:15) and to none other. (Rom. 10:14)
WCF 21.3.
Prayer, with thanksgiving, being one special part of religious worship, (Phil. 4:6) is by God required of all men: (Ps. 65;2) and, that it may be accepted, it is to be made in the name of the Son, (John 14:13–14, 1 Pet. 2:5) by the help of His Spirit, (Rom. 8:26) according to His will, (1 John 5:14) with understanding, reverence, humility, fervency, faith, love, and perseverance; (Ps. 47:7, Eccl. 5:1–2, Heb. 12:28, Gen. 18:27, James 5:16, James 1:6–7, Mark 11:24, Matt. 6:12, 14–15, Col. 4:2, Eph. 6:18) and, if vocal, in a known tongue. (1 Cor. 14:14)