Bede

He commanded them, among other things, to pray as follows: “And forgive us our debts as we forgive our debtors.” Or [it may be that] he calls his disciples “evil” because in comparison with the divine goodness, every creature is judged to be evil, as the Lord says, “No one is good except God alone.” It is only by participation in the divine goodness that a rational creature is recognized as being capable of becoming good. Hence the Lord also bears witness by a benevolent promise that your heavenly Father will “give the Holy Spirit to those who ask him.” This is to the point that those who of themselves are evil can become good through receiving the gift of the Spirit. He pledged that his good Spirit would be given by the Father to those asking for him, because whether we desire to secure faith, hope and charity, or any other heavenly goods at all, they are not bestowed upon us otherwise than by the gift of the Holy Spirit. So it is that the same spirit, in Isaiah, is named the spirit of wisdom and understanding, the spirit of counsel and fortitude, the spirit of knowledge and piety, the spirit of the fear of the Lord; and in another place, the spirit of love and peace, [and] the spirit of grace and prayer. Undoubtedly whatever good we truly have, whatever we do well, this we receive from the lavishness of the same Spirit. When a prophet who understood this was seeking purity of heart, saying, “Create a pure heart in me, O Lord,” he immediately added, “Renew an upright spirit in my inmost parts.” If the upright spirit of the Lord does not fill our innermost being, we have no pure heart where he may abide. When in his eager longing for and advance in good for his work he had said, “Lord, I have had recourse to you, teach me to do your will,” he at once showed in what way he had to secure this when he went on, “Let your good spirit lead me into the right way.”