Examples of God's different administrations over time

God’s accessibility has been, and will be, different across time:

From the creation of Adam and Eve until they sinned God in humanoid form walked and talked with them. Gen 3.8
From the beginning of sin to the inauguration of the Tabernacle God spoke occasionally/intermittently to individuals as He chose. Most of the God-man interactions were initiated by God, such as when God spoke to Cain (Gen 4.9-15), Noah (Gen 6.13-21, 7.1-4, 8.15-17, 9.1-17), Abram (Gen 12.1-3, 12.7, 13.14-17, 15.1-21, 17.1-23, 18.1-33, 22.1-2, 22.15-18) Hagar (Gen 16.7-14, 21.17-18), Abimelech (Gen 20.1-7), Jacob (Gen 28.13-15, 31.3, 32.24-29, 35.1, 35.9-12, 46.2-4), Laban (Gen 31.24), Moses (Ex 3.4-4.17, 4.19-22, 6.28-7.5, 7.8-9, 7.14-19, 8.1-5, 8.16, 8.20-23, 9.1-4, 9.8-9, 9.13-19, 9.22, 10.1-2, 10.12, 10.21, 11.1-2, 11.9, 12.1-27, 12.43-49, 13.1-2, 14.1-4, 14.15-18, 14.26, 16.4-5, 16.11-12, 16.28-29, 17.14; Num 1.1-16, 12.4, 13.1-2, 27.12-21, 28.1-29.39, 31.1-2, 31.25-30, 33.50-34.28, 35.1-34; Dt 32.48-52; etc.) and Aaron (Gen 4.27, 7.8-9, 16.9; Num 12.4-8), Miriam (Num 12.4-8), Balaam (Num 22.12, 22.20, 22.32-33, 22.35, 23.4-5, 23.16), and Joshua (Josh 1.1-9, 3.7-8, 4.15, 5.2, 5.13-6.5, 8.1-2). The accounts of people initiating contact with God through prayer, are fewer. Examples include Abraham’s servant (Gen 24.12-14), Moses (Ex 5.22-6.8, 8.12-13, 10.18-19; Num 12.13-14). Most such occurrences are about questions brought to God about governing/leading Israel or military decisions. Examples are Moses (Ex 15.25, 17.4-6; Num 27.5-11; etc.) and Joshua (Josh 7.6-15).
From the Tabernacle until the time when God’s presence departed the Temple (Eze 10.4, 18-19, 11.23) God was accessible through priests according to strict procedures in the Sinaitic/Mosaic Law, and always qualified by a sin offering of the death of a sacrificial animal.
From God’s glory having abandoned the Temple to Pentecost there was no established way for man to initiate contact with God; so access to God varied as God initiated contact with individuals for specific purposes, sometimes directly and sometimes through angelic messengers. Examples are Zechariah (Lk 1.11-20), Mary (Lk 1.26-38), Joseph (Mt 1.20-23), and Simeon (Lk 2.26).
From Pentecost onward, access to God by those reconciled to Him (also identified as “those Christ has redeemed”, and here termed “the believer”) has been and is continuous and bi-directional. God continuously speaks in words through the Scriptures He inspired, and in various ways through His Holy Spirit continuously and permanently indwelling the believer. The believer has the authorization and ability to reach out to God anytime in prayer, with the guaranteed assurance that the prayer will be received according to God’s grace, will be enhanced and refined by the representative advocacy of the Holy Spirit, and will be further supported by the intercession of the Son.
In the future era when God the Son is physically dwelling on earth with the believers, access to God will be physical and personal through the presence of the Lord, Jesus, the Christ. Since God has declared the eternal permanence of His Word, that method of God-to-man access will continue. In this era, since there is no Biblical indication otherwise, the man-to-God access method of prayer is thought to also be continuously available. Since Jesus, the Christ, in His redemptive mission voluntarily suspended the use of His omnipresence capability, in the flesh He will probably occupy only one physical location on earth at a time. If so, then physical access to Him will be limited to the times when a believer is enabled to be physically near Him. Finally, as Scripture says a glorified believer’s body will be like Christ’s resurrected body, and since Christ in this body was able to instantaneously and miraculously transport his body to different locations, this capability might be shared with the glorified believers. If so, they will be able to instantly and at will move their body to different locations, making their being in Christ’s proximity much easier.

God dealing with sin.