I think this question could be improved, but I’m not sure how I’d change it. I’d like to take out the phrase “covenant of Grace,” because, for one, none of the texts say anything about it. (They can’t, because the phrase isn’t found in scripture.) I think “work of salvation” or something like that would be better.
Would you change it? How?
Part III: Questions about Salvation
101. Q. What did the Holy Spirit undertake in the covenant of Grace?
A. He regenerates, baptizes, and seals those for whom Christ has died.
(Click through to read scriptural proof.)
And you were dead in the trespasses and sins  in which you once walked, following the course of this world, following the prince of the power of the air, the spirit that is now at work in the sons of disobedience— among whom we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind.  But God, being rich in mercy, because of the great love with which he loved us,  even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved— and raised us up with him and seated us with him in the heavenly places in Christ Jesus,  so that in the coming ages he might show the immeasurable riches of his grace in kindness toward us in Christ Jesus.  For by grace you have been saved through faith. And this is not your own doing; it is the gift of God … .
For in one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit,  who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.
And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.
…and who has also put his seal on us and given us his Spirit in our hearts as a guarantee.