What do I need to seek being closer to him?
3 Jesus answered and said to him: Amen, amen, I say to thee, unless a man be born again, he cannot see the kingdom of God.
4 Nicodemus saith to him: How can a man be born when he is old? Can he enter a second time into his mother's womb and be born again?
5 Jesus answered: Amen, amen, I say to thee, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God.
6 That which is born of the flesh is flesh: and that which is born of the Spirit is spirit.
7 Wonder not that I said to thee: You must be born again.
8 The Spirit breathes where he will and thou hear his voice: but thou know not whence he comes and whither he goes.
So is every one that is born of the Spirit.
John 3:3-8
Start by reading the gospel of John, which explains that believers would receive the indwelling Holy Spirit - the Spirit of truth.
Jesus and the Father residing in you, teaching you, leading you, empowering you.
You cannot get any closer than by having God within you; experiencing God.
Act 2:38 Then Peter said to them, Repent and be baptized, every one of you, in the name of Jesus Christ to remission of sins,
and you shall receive the gift of the Holy Spirit.
Act 2:39 For the promise is to you and to your children, and to all those afar off, as many as the Lord our God shall call.
Acts 2:38-39
You will speak (or rather pray) in 'tongues' - a spiritual language belonging to God and the angels. You will pray with power
and conviction, and thereby enjoy many miracles and healings, and increase your faith and joy.
20 But you, beloved, building yourselves up in your most holy faith,
praying in the Holy Spirit,
21 keep yourselves in the love of God, eagerly awaiting the mercy of our Lord Jesus Christ to everlasting life.
Jude 1:20-21