Knowing how to worship God in Spirit and Truth is crucial for faith to meet God's expectation. Jesus was bringing out to the woman at the well that following the traditions of man is not the same as meeting the expectations of God; righteousness is not attained by man's best intentions, nor by relying on such traditions of faith as one might have grown up in.
For faith to meet God's expectation there needs be obedience to His terms - which terms is made known through the Steward of His election. As such, in saying "God is a Spirit: and they that worship him MUST worship him in spirit and in truth" (John 4:24), He was showing Himself as that new Steward.
John 14:6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Abraham was a Steward through whom God gave instruction to build altars on mountains, which was a sanctified means of worship AT THAT TIME. Moses was a Steward through whom God gave instruction to build a tabernacle to house His altar; making the altars on the mountain NO LONGER SANCTIFIED for service, as the sanctification was now on the Covenant of Moses, and the terms of the Levitical priesthood defined by God AT THAT TIME.
Christ fulfilled in Himself all things of that covenant and by His blood purchased unto us a new and better Spiritual Covenant. This is what He was making reference to - a Covenant wherein He will be the Point of Sanctification in a Priesthood of Spirit and Truth; i.e requiring both the present indwelling of His Holy Spirit (through the baptism of the Holy Spirit, evidenced by tongues), AND His Holy Knowledge (the foundation of Truth, laid in the heart of believers by living covenant apostles of Jesus Christ).
Truth, thus, are facts which are consistent with God's character, purpose and plan. Jesus BEING the TRUTH, speaks of that which He says, what He does, and the product of His work within the converted covenant believer. To worship God in Truth, means to worship God according to the terms of Christ's Covenant; in obedience to His knowledge / true doctrine. Without sanctified Stewardship, that becomes open to interpretation to believers, and so you see the 30 000 odd versions of Christianity currently in the world; in contrast with the One Truth (Doctrine of Christ) that united the first Church in One understanding.
1Peter 1:22 Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently:
To meet God's Standard in Jesus Christ, one needs to come into Covenant with Him, and receive the foundation of His Truth upon which to rightly build faith according to that One Blueprint which Jesus entrusted to the Apostles; as referred to by the Apostle Paul:
1Cor 3:10 According to the grace of God which is given unto me, as a wise masterbuilder, I have laid the foundation, and another buildeth thereon. But let every man take heed how he buildeth thereupon.
God has in our time restored this Holy Knowledge for the restoration of His Church. I will quote a section here from the link that will follow, where you can gain further info:
Truth is the element that tells us that we need knowledge for faith and knowledge to reciprocate to God on His level. Faith builds with knowledge. Jesus Christ is truth, meaning that He is the record, blueprint, and pattern of our faith, which we follow. Jesus swore by Himself to be the eternal pattern/record for salvation; He is the law and principle we are to follow for righteousness. God’s will is that we would know Him only by the properties of Himself. Truth cleanses and nourishes the soul. John 14:4