1 In the beginning, therefore, did God form Adam, not as if He stood in need of man, but that He might have [some one] upon whom to confer His benefits. For not alone antecedently to Adam, but also before all creation, the Word glorified His Father, remaining in Him; and was Himself glorified by the Father, as He did Himself declare, “Father, glorify Me with the glory which I had with You before the world was.” Nor did He stand in need of our service when He ordered us to follow Him; but He thus bestowed salvation upon ourselves. For to follow the Saviour is to be a partaker of salvation, and to follow light is to receive light. But those who are in light do not themselves illumine the light, but are illumined and revealed by it: they do certainly contribute nothing to it, but, receiving the benefit, they are illumined by the light. Thus, also, service [rendered] to God does indeed profit God nothing, nor has God need of human obedience; but He grants to those who follow and serve Him life and incorruption and eternal glory, bestowing benefit upon those who serve [Him], because they do serve Him, and on His followers, because they do follow Him; but does not receive any benefit from them: for He is rich, perfect, and in need of nothing. But for this reason does God demand service from men, in order that, since He is good and merciful, He may benefit those who continue in His service. For, as much as God is in want of nothing, so much does man stand in need of fellowship with God. For this is the glory of man, to continue and remain permanently in God's service. Wherefore also did the Lord say to His disciples, “You have not chosen Me, but I have chosen you;” indicating that they did not glorify Him when they followed Him; but that, in following the Son of God, they were glorified by Him. And again, “I will, that where I am, there they also may be, that they may behold My glory;” not vainly boasting because of this, but desiring that His disciples should share in His glory: of whom Esaias also says, “I will bring your seed from the east, and will gather you from the west; and I will say to the north, Give up; and to the south, Keep not back: bring My sons from far, and My daughters from the ends of the earth; all, as many as have been called in My name: for in My glory I have prepared, and formed, and made him.” Inasmuch as then, “wheresoever the carcass is, there shall also the eagles be gathered together,” we do participate in the glory of the Lord, who has both formed us, and prepared us for this, that, when we are with Him, we may partake of His glory.
2. Thus it was, too, that God formed man at the first, because of His munificence; but chose the patriarchs for the sake of their salvation; and prepared a people beforehand, teaching the headstrong to follow God; and raised up prophets upon earth, accustoming man to bear His Spirit [within him], and to hold communion with God: He Himself, indeed, having need of nothing, but granting communion with Himself to those who stood in need of it, and sketching out, like an architect, the plan of salvation to those that pleased Him. And He did Himself furnish guidance to those who beheld Him not in Egypt, while to those who became unruly in the desert He promulgated a law very suitable [to their condition]. Then, on the people who entered into the good land He bestowed a noble inheritance; and He killed the fatted calf for those converted to the Father, and presented them with the finest robe. Thus, in a variety of ways, He adjusted the human race to an agreement with salvation. On this account also does John declare in the Apocalypse, “And His voice as the sound of many waters.” For the Spirit [of God] is truly [like] many waters, since the Father is both rich and great. And the Word, passing through all those [men], did liberally confer benefits upon His subjects, by drawing up in writing a law adapted and applicable to every class [among them].
3. Thus, too, He imposed upon the [Jewish] people the construction of the tabernacle, the building of the temple, the election of the Levites, sacrifices also, and oblations, legal monitions, and all the other service of the law. He does Himself truly want none of these things, for He is always full of all good, and had in Himself all the odour of kindness, and every perfume of sweet-smelling savours, even before Moses existed. Moreover, He instructed the people, who were prone to turn to idols, instructing them by repeated appeals to persevere and to serve God, calling them to the things of primary importance by means of those which were secondary; that is, to things that are real, by means of those that are typical; and by things temporal, to eternal; and by the carnal to the spiritual; and by the earthly to the heavenly; as was also said to Moses, “You shall make all things after the pattern of those things which you saw in the mount.” For during forty days He was learning to keep [in his memory] the words of God, and the celestial patterns, and the spiritual images, and the types of things to come; as also Paul says: “For they drank of the rock which followed them: and the rock was Christ.” And again, having first mentioned what are contained in the law, he goes on to say: “Now all these things happened to them in a figure; but they were written for our admonition, upon whom the end of the ages has come.” For by means of types they learned to fear God, and to continue devoted to His service.
Source: Adversus haereses (New Advent)