The greatest difference in the Bible "before Christ" and "after Christ" is the indwelling of the Spirit in every Christian: Before Christ, the Spirit was "upon the people", after Christ the Spirit is "in the people". The Holy Spirit is always all over, like the air we breed, but he dwells in every Christian, he makes "his home" in every Christian. Even in the time that Jesus lived, "the Spirit had not yet been given because Jesus had not yet entered into his Glory" (Jn.7:37).

    In the Sermon of the Last Supper, Jesus told the disciples, "you know the Spirit for he is with you and will be in you" (Jn.14:17): He was already "with them", but not yet "in them". He was "with them", as he was with the good people in the Bible and in the world before Christ, but after the glorification of Jesus, he will be "in them".

    The Holy Spirit indwells in each Christian from the moment of the Sacramental Baptism, from the new birth in Christ, every Christian is temple of the Holy Spirit, the home of the Holy Spirit (Jn.3, 1Cor.3:16, 6:19-20, Rom.8:11. 2Tim.1:14)… and Jesus and the Father make their home in the Christian, alleluia, we are temples of God (Jn.14:23, 1Cor.3:16).

    Of course, all the good work of the people before Christ was made by the power of the Holy Spirit who was "with" them or "upon them": Like Gideon and Jephthah and Samson (Jud.6:34, 11:29, 13:25, 14:6,19), and like Moses, Bezalel, David, Isaiah, Ezekiel, Micah… (Ex.11:17, 31:3, 1S.16:13, Is.11:2, Ez.11:5, Mi.3:8)… and even John the Baptist, the greatest of the prophets, is smaller that anyone in the Kingdom, because Jesus was not in him yet by the power of the Spirit (Mt.11:11, Lk.7:28).

2- The "Seal" with the Spirit:

    At the moment of the Sacramental Baptism we were justified, regenerated, born again, born into the body of Christ, and we became temples of God… but other events took place, like the seal and pledge and witness of the Holy Spirit:

    We were "sealed" or "marked" with the Holy Spirit, mentioned three times (Eph.1:13, 4:30, 2Cor.1:22).

    The "seal" is for "security", like when Pilate put the seal on the tomb of Jesus for security, nobody could open it! (Mt.27:65-66)... it is a most thrilling thought: When we were sealed with the Holy Spirit, we were secure in Christ.

    And the seal is also a "mark of ownership", like when Jeremiah bought a property and the document was sealed, he was now the owner! (Jer.32:10: A Christian is God's property, forever!. 

3- The "Pledge" of the Spirit:

    God gave us the Spirit in our hearts as "a pledge of what we shall receive", as "a first installment", mentioned three times (2Cor.1:22, 5:5, Eph.1:14).

    This pledge or first installment, like any other business pledge, means three glorious things:
    1- It was a down payment that sealed a bargain.
    2- It represents an obligation to pay the whole price at the convened time, a "guarantee": The presence of the Holy Spirit in us shows an obligation of God to redeem us completely, guaranteeing our inheritance until the future brings the total redemption of those who are God's possession.
    3- It is a foretaste, a sample, of our coming life and inheritance in God's presence:

    This pledge is part of a payment and secures the full sum: The Spirit's sanctification on earth is a pledge of perfect holiness. The Spirit's illumination is a pledge of everlasting full light. His comforts are a pledge of everlasting full joys. The life of Christian on earth is but a foretaste of Heaven, praise God.

4- The "Witness" of the Spirit:

    The Holy Spirit is also our witness within, assuring us of the reality of our salvation in Jesus Christ (Heb.10:14-18). "The Spirit Himself bears witness with our spirit that we are children of God" (Rom.8:16, Gal.4:6-7). Only with the power of Spirit we can realize and live the fact that God is our Father, and only with the Spirit we can proclaim "Jesus is the Lord" (1Cor.12:3)… this is actually the Magna Charta of the Christian's liberation from the power of sin to the privileges and wealth of Christ. Every day we should shout often, "Abba, Father", "Jesus is the Lord", praise the Holy Spirit, the Lord, the giver of life!.