Not everyone who says to me, "Lord, Lord",
will enter the kingdom of heaven,
but only the one who does the will of my Father in heaven.

Matt. 7, 21

St. Sister Faustina about God's will

(Selected parts of the Diary of St. Faustina Kowalska)

Faithful submission to the will of God, always and everywhere, in all events and circumstances of life, gives great glory to God. Such submission to the will of God carries more weight with Him than long fasts, mortifications and the most severe penances. Oh, how great is the reward for one act of loving submission to the will of God! As I write, my soul is enraptured at the thought of how much God loves it and of the peace that my soul already enjoys, here on earth (Diary 724)

Today during meditation, God gave me inner light and the understanding as to what sanctity is and of what it consists. Although I have heard these things many times in conferences, the soul understands them in a different way when it comes to know of them through the light of God which illumines it. 

Neither graces, nor revelations, nor raptures, nor gifts granted to a soul make it perfect, but rather the intimate union of the soul with God. These gifts are merely ornaments of the soul, but constitute neither its essence nor its perfection. My sanctity and perfection consist in the close union of my will with the will of God. God never violates our free will. It is up to us whether we want to receive God's grace or not. It is up to us whether we will cooperate with it or waste it (Diary 1107)

Perfect fulfillment of God's will is maturity in sanctity; there is no room for doubt here. To receive God's light and recognize what God wants of us and yet not do it is a great offense against the majesty of God. Such a soul deserves to be completely forsaken by God (Diary 666).

True love of God consists in carrying out God's will. To show God our love in what we do, all our actions, even the least, must spring from our love of God (Diary 279).

The essence of the virtues is the will of God. He who does the will of God faithfully, practices all the virtues (Diary 678)