Why are we to pray in the name of Christ?
The sinfulness of man, and his distance from God by reason thereof, being so great, as that we can have no access into his presence without a mediator;1 and there being none in heaven or earth appointed to, or fit for, that glorious work but Christ alone,2 we are to pray in no other name but his only.3
Scripture proofs
The Westminster Assembly's proof texts (KJV). The bracketed numbers in the answer above mark the clause each set of references supports; expand a row to read the verses.
1 John 14:6; Isa. 59:2; Eph. 3:12
Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear.
In whom we have boldness and access with confidence by the faith of him.
2 John 6:27; Heb. 7:25–27; 1 Tim. 2:5
Labour not for the meat which perisheth, but for that meat which endureth unto everlasting life, which the Son of man shall give unto you: for him hath God the Father sealed.
Heb. 7:25 Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever liveth to make intercession for them.
Heb. 7:26 For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens;
Heb. 7:27 Who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people’s: for this he did once, when he offered up himself.
For there is one God, and one mediator between God and men, the man Christ Jesus;
3 Col. 3:17; Heb. 13:15
And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him.
By him therefore let us offer the sacrifice of praise to God continually, that is, the fruit of our lips giving thanks to his name.
This doctrine across the Standards
Where the Confession and the Westminster Shorter Catechism treat the same matter, so the question can be studied alongside its parallel statements.
In the Westminster Confession
XXI.3 Prayer with thanksgiving, being one special part of religious worship, is by God required of all men; and …
Prayer with thanksgiving, being one special part of religious worship, is by God required of all men; and that it may be accepted, it is to be made in the name of the Son, by the help of his Spirit, according to his will, with understanding, reverence, humility, fervency, faith, love, and perseverance; and, if vocal, in a known tongue.
→ XXI.3 · Of Religious Worship and the Sabbath DayXXI.4 Prayer is to be made for things lawful, and for all sorts of men living, or that shall …
Prayer is to be made for things lawful, and for all sorts of men living, or that shall live hereafter; but not for the dead, nor for those of whom it may be known that they have sinned the sin unto death.
→ XXI.4 · Of Religious Worship and the Sabbath DayIn the Westminster Shorter Catechism
Q.98 What is prayer?
Prayer is an offering up of our desires unto God, for things agreeable to his will, in the name of Christ, with confession of our sins, and thankful acknowledgement of his mercies.
→ Open Q.98Q.99 What rule hath God given for our direction in prayer?
The whole Word of God is of use to direct us in prayer; but the special rule of direction is that form of prayer which Christ taught his disciples, commonly called The Lord's Prayer.
→ Open Q.99Q.100 What doth the preface of the Lord's Prayer teach us?
The preface of the Lord's Prayer, which is, Our Father which art in heaven, teacheth us to draw near to God with all holy reverence and confidence, as children to a father, able and ready to help us; and that we should pray with and for others.
→ Open Q.100Q.101 What do we pray for in the first petition?
In the first petition, which is, Hallowed be thy name, we pray, that God would enable us, and others, to glorify him in all that whereby he maketh himself known; and that he would dispose all things to his own glory.
→ Open Q.101Q.102 What do we pray for in the second petition?
In the second petition, which is, Thy kingdom come, we pray, that Satan's kingdom may be destroyed; and that the kingdom of grace may be advanced, ourselves and others brought into it, and kept in it; and that the kingdom of glory may be hastened.
→ Open Q.102Q.103 What do we pray for in the third petition?
In the third petition, which is, Thy will be done in earth, as it is in heaven, we pray, that God, by his grace, would make us able and willing to know, obey, and submit to his will in all things, as the angels do in heaven.
→ Open Q.103Q.104 What do we pray for in the fourth petition?
In the fourth petition, which is, Give us this day our daily bread, we pray that of God's free gift we may receive a competent portion of the good things of this life, and enjoy his blessing with them.
→ Open Q.104Q.105 What do we pray for in the fifth petition?
In the fifth petition, which is, And forgive us our debts, as we forgive our debtors, we pray that God, for Christ's sake, would freely pardon all our sins; which we are the rather encouraged to ask, because by his grace we are enabled from the heart to forgive others.
→ Open Q.105Q.106 What do we pray for in the sixth petition?
In the sixth petition, which is, And lead us not into temptation, but deliver us from evil, we pray, that God would either keep us from being tempted to sin, or support and deliver us when we are tempted.
→ Open Q.106Q.107 What doth the conclusion of the Lord's Prayer teach us?
The conclusion of the Lord's Prayer, which is, For thine is the kingdom, and the power, and the glory, for ever, Amen. teacheth us to take our encouragement in prayer from God only, and in our prayers to praise him, ascribing kingdom, power, and glory to him; and, in testimony of our desire, and assurance to be heard, we say, Amen.
→ Open Q.107