In short, for answering of this question, I shall lay down those particulars:
1. There should be a lively sense of the infinite distance that is between the great God and us finite creatures, and yet more betwixt the Holy Ghost and us sinful wretches.
2. There should be an eyeing of Christ as the great peacemaker, through his death and merits having satisfied justice and reconciled sinners unto God; that so we may look on God now no more as an enemy, but as reconciled in Jesus.
3. There should be, sometimes at least, a more formal and explicit actual closing with Christ as ours, when we are going about such duties, and always an implicit and virtual embracing of him as our Mediator, or an habitual hanging upon him and leaning to him as our Mediator and peacemaker.
4. There should be an eyeing of him as our great High Priest now living for ever to make intercession for us, and to keep the door of heaven open to us: upon which account the apostle presseth the Hebrews to "come boldly to the throne of grace," Heb. iv. 14,16. See also Heb. v. 24,25.
5. There should be a gripping to him even in reference to that particular act of worship, and a laying hold upon him, to speak so, as our master-usher to bring us by the hand in to the Father, conscious of our own unworthiness.
6. There should be a confident leaning to him in our approaching, and so we should approach him without fear and diffidence; and that notwithstanding that we find not our souls in such a good frame as we would Wish, yea, and guilt looking us in the face.
7. Thus should we roll all the difficulties that come in our way, and all the discouragements which we meet with, on him, that he may take away the one and the other, and help us over the one and the other.
8. As we should take an answer to all objections from him alone, and put him to remove all scruples and difficulties, and strengthen ourselves against all impediments and discouragements alone, in and through him, so there should be the bringing of all our positive encouragements from him alone, and all our hopes of coming speed with the Father should be grounded upon him.
9. We should expect all our welcome and acceptance with the Father only in and through Christ, and expect nothing for any thing in ourselves, nor for our graces, good frame, preparation, or any thing of that kind. So we should not found our acceptance nor our peace and satisfaction on ourselves, nor on any thing we have or do; nor should we conclude our exclusion or want of acceptance, because we do not apprehend our frame so good as it ought to be; so we should not found our acceptance on our right performance of duties, for that is not Christ.
10. We should quiet ourselves on him alone in all our approaches, whatever liveliness we find or miss in duty. We are too much tickled and fain when duties go well with us, and troubled on the other hand when it is not so; and the ground of all this is, because we lean too much to our own duties, and do not quiet ourselves on him alone. And hence it is, that we are often quieted when we get the duty done and put by, though we have not met with him there, nor gotten use made of him as was necessary. All our comfort, peace, and quiet should be founded on him alone.
11. We should look to him for the removal of all the discouragements that Satan casts in our way while we are about this or that piece of worship, to put us back, or cause us to advance slowly and faintingly; and casting them all on him, go forward in our duty.
12. We should look for all our returns and answers only in and through him, and lay all the weight of our hopes and expectations of a good answer only on him, 1 John v. 13, 14, 15.
For caution I would add a word or two:
1. I do not think that the believer can explicitly and distinctly act all these things whenever he is going to God, or can distinctly perceive all these several acts; nor have I specified and particularly mentioned them thus, for this end, but to shew at some length, how Christ is to be employed in those acts of worship which we are called to perform; and that because we oftentimes think the simple naming of him, and asking of things for his sake, is sufficient, though our hearts lean more to some other thing than to him; and the conscientious Christian will find his soul, when he is rightly going about the duties of worship, looking towards Christ thus, sometimes more distinctly and explicitly as to one particular, and sometimes more as to another.
2. Though the believer cannot distinctly act faith on Christ all these ways, when he is going about commanded duties of worship, yet he should be sure to have his heart going out after Christ, as the only ground of his approaching to and acceptance with and of being heard by the Father; and to have his heart in such an habitual frame of resting on Christ, that really there may be a relying upon him all these ways, though not distinctly discerned.
3. Sometimes the believer will be called to be more distinct and explicit in looking to and resting upon Christ, as to one particular, and sometimes more as to another. When Satan is dissuading him to go to God because he is an infinitely holy One, and he himself is but a sinner, then he is called to act faith on Christ as the Mediator making reconciliation between God and sinners; and when Satan is dissuading from approaching to God, because of their want of an interest in God, then should they act faith on Christ, and embrace him according to the gospel, and rest there, and so approach. And when Satan casts up his unworthiness and former sins, to keep him a-back or to discourage him, then he is called to lay hold on Christ as the great High Priest and Advocate, and casting that discouragement on him, to go forward. So likewise, when Satan is discouraging him in his duty, by bringing before him his sins, he should take this course; and when, because of his sinful way of worshipping God, and calling upon him, and other things, he is made to fear that all is in vain, and that neither God regardeth him nor his services, and that he shall not come speed, then should he cast all the burden of his acceptance, and of obtaining what he asketh and desireth, on Christ, and quiet himself there; and so as to the rest. And hence appeareth the usefulness of our branching out of this matter.
4. In all this, there must be an acting in the strength of Jesus; a looking to Christ and resting upon Christ, according to the present case and necessity, in Christ; that is, by his strength and grace communicated to us by his Spirit; then do we worship God in the Spirit, and in the newness of the Spirit, when all is done, in the matter of worship, in and through Jesus.