Sanctifying grace is the supernatural life of the soul. It is absolutely necessary for eternal salvation. It makes us children of God and enables us to share in the divine life of God.
St. Francis de Sales valued sanctifying grace more than the gift of working miracles. He said, “One ounce of sanctifying grace is worth more than a hundred pounds of those graces which theologians call ‘gratuitous,’ of which the gift of miracles is one. Indeed, one may receive such gifts and still be in mortal sin; nor are they by any means essential to salvation. But the man who has received even the smallest degree of justifying or sanctifying grace is assured of victory.”
Both the sacraments of baptism and penance infuse sanctifying grace into the soul. Sanctifying grace is lost by deliberate mortal sin. Hence, having no consciousness of any mortal sin committed after baptism that has not been cleansed by the sacrament of penance is a sign that the person is in the state of grace.
St. Francis de Sales pointed out two other signs which indicate a person is in the state of grace. He said: “Probe your interior life with the searching light of self-examination and see whether you really have a strong, unswerving determination never to offend God willingly and deliberately. For it is precisely in this that union with His will primarily rests, since He wants our grace and sanctification above everything else. Secondly, see whether you are moved by a strong, sincere desire to love God, a desire which does not stop short in mere thought and imagination, but proceeds to action.”
The saint said, “To die in God means to die in the grace of God, because God is no more separated from His grace than the sun from its rays.”
In order to attain eternal life, it is enough to die in sanctifying grace. For those who die in the state of grace, though they may never have performed a single charitable act (as in the case of baptized infants), gain paradise by right of inheritance. Those who die in the state of grace while engaged in acts of charity attain heaven by a double title, that of inheritance and of reward.
Regarding good natural inclinations St. Francis de Sales said, “If you possess such, remember that they are gifts, of which you will have to render an account. Take care, then, to employ them in the service of Him who gave them to you. Engraft upon this wild stock the shoots of eternal love which God is ready to bestow upon you, if, by an act of perfect self-renunciation, you prepare yourself to receive them.”
The saint warned people not to keep their talents wrapped up in a napkin, and not to hide their light under the bushel of nature, but to trade with them according to the intention of him who is their author and distributor.
There are four kinds of good works: living, dead, dying, and revivified. Living works are those performed in the state of grace. Dead works are those performed in the state of mortal sin. Though the works contain some natural virtues, they cannot bring forth leaves or good fruits to God, since they are not rooted in charity.
Dying works are performed in the state of grace, but then overtaken by mortal sin and hence deprived of all life and vigor. Revivified works are those which once dying are called to new life by the grace of God. This happens when a person repents from mortal sin and is restored to the state of grace.
聖寵使善功更具活力
寵愛是靈魂的超性生命。為永恆的救恩是絕對需要的。它讓我們成為天主的子女，使我們分享天主的至聖生命。聖方濟、沙雷氏珍惜這寵愛尤甚於行使奇蹟的恩寵。一安士的寵愛要勝於一百磅的神恩，行奇蹟是其中之一。真的，一個人在大罪中的也可能得獲神恩，這些神恩在救恩中不是必然的。但一個人，他能得到最少程度的寵愛就可以確保勝算。』
聖洗聖事和修和聖事兩者都把聖化聖寵注諸靈魂中。寵愛因故意的大罪而失落。所以，領洗後，沒有明知故犯的，未為修和聖事清潔大罪的人都有跡象顯示他是在寵愛中。
聖方濟、沙雷氏指出兩個其他的跡象，都能顯示一個人在聖寵中。他說：『以自我檢測的搜索燈，探索你生命內心，一看你是否真的有一堅強的，始終如一，永不願意和故意冒犯天主的決心。因為這就是準確地與祂旨意結合要點所在，因為祂願我們聖寵及聖化在所有一切之上。其次是一看你是否為一堅強，誠意愛天主的渴望所動，—個渴望甚至在腦海中，想象中亦不會短暫停止，但卻施諸行動。』
這位聖人說：『死於主內是說死於天主聖寵之內，因為天主與祂的聖寵不會分離，相對於太陽與光線。』要能獲得永恆生命，只要能死於聖化聖寵中便可。因為那些死於聖寵光景下的，雖然他們可能從沒有行過一個善功（例如剛領洗的嬰孩），因著承繼權而得進天堂。那些在寵愛中死亡的，也曾作過善功的以兩種名銜抵步天堂…就是承繼和賞報。
有關好的自然的傾向，聖方濟、沙雷氏說：『如果你能擁有這些，請記得它們都是恩典，你將要為了它們而交賬。要當心把它們用於服務天主中，是祂惠施與你的。要在這野生種群接枝永恆之愛的芽。如果你秉承完全自我棄絕的情操準備好去接受，天主準備把這芽賜給你。』這聖人警告我們，不要以手帕包裹著你己的天才，不要把它們的光芒隱蔽，但按天主的聖意使用它。一切才華都是祂所創做和分發的。
善功有四種：活著的，死的，死亡中的和再具活力的。活著的善功是那些在聖寵狀態下做的。死的善功是在有大罪狀態下作的。雖然這工作包含有自然的美德，但它們不能為天主帶來樹葉和果實，因為它們並不是根生於愛德。
死亡中的善工是在聖寵狀態下作的，但其後為大罪所取締，因此奪去了它的生命和活力。再具活力的善工是那些曾一度死亡卻為天主的聖寵再獲新生。當人從大罪中悔改回來並重回聖寵狀態，死亡的善功便再具活力。