How can the believer constantly grow and mature spiritually?

St. Augustine says, “During the fast, the catechumens are grinded like wheat, kneaded with water in baptism, shaped like the body of Christ, and are baked by the fire of the Holy Spirit through the anointing of the Chrism.” In the Third Hour Prayer (Agpeya) we say, “Your Holy Spirit, O Lord whom You sent down upon Your holy disciples and honored apostles in the third hour, do not take Him away from us, O Good One, but we ask You to renew Him within us. Create in me a clean heart, O God, and renew a right spirit within me.” St. Irenaeus also says, “those upon whom the apostles laid hands received the Holy Spirit, who is the food of life [eternal]”¹⁴⁰⁶ (compared to the milk on which St. Paul said they fed (see 1 Cor. 3:2)).