"Who is there who speaks and it happens — unless the Lord has ordained it?" Lamentations 3:37 - John Newton

We have no Scriptural evidence that we serve the Lord at all, any farther than we find a habitual desire and aim to serve him wholly.
He is gracious to our imperfections and
weakness; yet he requires all the heart, and
will not be served by halves, nor accept what is performed by a divided heart.

The appearance of an angel from heaven could add nothing to the certainty of the declarations he has already put into our hands.

When our hopes are most alive, it is less from a view of the imperfect beginnings of grace in our hearts, than from an apprehension of him who is our all in all. His person, his love, his sufferings, his intercession, his compassion, his fullness, and his faithfulness — these are our delightful themes, which leave us little leisure, when in our best frames, to speak of ourselves... If any people have contributed a mite to their own salvation, it was more than we could do. If any were obedient and faithful to the first calls and impressions of his Spirit, it was not our case. If any were prepared to receive him beforehand, we know that we were in a state of alienation from him. We needed sovereign, irresistible grace to save us, or we would be lost forever! If there are any who have a power of their own, we must confess ourselves poorer than they are. We cannot watch, unless he watches with us; we cannot strive, unless he strives with us; we cannot stand one moment, unless he holds us up; and we believe we must perish after all, unless his faithfulness is engaged to keep us. But this we trust he will do, not for our righteousness, but for his own name's sake, and because, having loved us with an everlasting love, he has been pleased in loving kindness to draw us to himself, and to be found by us when we sought him not.