How do Jesus' words in Matthew 7 apply to us today?
Answer: John 3:5, 1 Cor. 11:24-26 (per Lk. 22:19-20).
It took me quite a bit of study to finally understand what Christ is saying in the passage below. I've finally come to recognize what He was proclaiming (I've paraphrased):
John 3:5: "[Unless] one is born of water and [born of] the Spirit he cannot enter into the kingdom of God" (emphasis added).
I. Since the words of the Son of God are absolutely paramount: What does it mean to be born of water? While many may deny this as unnecessary, there is really only one answer to the question: baptism — water immersion into Christ.
I won't take the time here to enumerate the dozens of passages that speak to baptism other than to suggest that it is a crucial mistake to believe that water immersion, baptism, is merely "an outward sign of an inner grace." The simple reason is that such claims advance the false notion that baptism is optional: it is not. The idea of an unbaptized Christian is simply nowhere entertained in the New Testament.
The reason that baptism is so important is that upon submission to this rite, we are cleansed of our old selves: that is how we crucify ourselves, to then be resurrected just as Paul explains:
Romans 6:3-4: "[Do] you not know that all of us who have been baptized into Christ Jesus have been baptized into His death? Therefore we have been buried with Him through baptism into death, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life" (emphasis added).
Note this too: It is God Who performs the spiritual cleansing. The cleansing is an act of God (1 Jn. 1:7, 9). All we are doing is obeying Christ's commandment.
II. Another question then arises: "What does it mean to be 'born of the Spirit?'" There is an answer to this, but it is not the same thing as that which occurred on Pentecost in the first century.
Let us understand that the Spirit is illuminated in the Bible. While Scripture was written by men, it has been infallibly delivered to us by the Holy Spirit. Once we understand that "the Spirit" in John 3:5 is the manifestation of the Holy Spirit in Scripture, then it follows that we must immerse ourselves in the words, the revelation from the Spirit of God. This, I propose, is how we are "born of the Spirit."
As we do this, we are internalizing the Mind of God, replacing our old worldly mentality with the Mind of Christ. Paul articulates this renewal of our minds in his Letter to the Romans:
Romans 12:2: "And do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what the will of God is, that which is good and acceptable and perfect" (emphasis added).
When we do this, and we arrive at a crossroad where one path leads to sin, and another leads to righteousness, because we possess part of God's Mind through the Spirit, we know how to avoid "grieving the Holy Spirit" (Eph. 4:30) by choosing the path that leads to righteousness — something that we heretofore may never have understood, being overwhelmed by worldliness.
III. How does Paul's First Letter to the Corinthians apply to the question?
1 Corinthians 11:24-26: "[When Christ] had given thanks, He broke [the bread] and said, 'This is My body, which is for you; do this in remembrance of Me.' In the same way He took the cup also after supper, saying, 'This cup is the new covenant in My blood; do this, as often as you drink it, in remembrance of Me.' For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until He comes" (cf. Lk. 22:19-20, emphasis added).
Are these mere suggestions by Christ? Most will recognize such commandments as the Lord's Supper, communion, which consists of 1) unleavened bread, and 2) fruit of the vine (grape juice). This rite represents a "common union" with Christ and the rest of the saints on the Lord's Day (Sunday).
These too are not optional as many suppose. This is direct proclamation by the Son of God, something that we may often dismiss or even reject entirely as part of our worship — to our peril. Too often, we like to have everything our way, to have our "ears tickled" rather than to submit to God's desires for us:
1 Timothy 4:3: "For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires."
Many will claim that they "feel" the Spirit within them. I have no desire to begrudge anyone of their peace and happiness in Christ. But if we do not obey the simple commandments spoken by Christ in John 3:5 (and Lk. 22:19-20), how is that not sin, disobedience, and lawlessness?
If we neglect these vital aspects of salvation, we are no better off than those who prophesied or cast out demons or performed miracles in the name of Christ and were subsequently rejected by Him. God is only impressed with our obedience to the Gospel:
John 14:15: “If you love Me, you will keep My commandments."
To love Christ is to obey Him. This verse might otherwise be rendered: "If you do not keep My commandments you do not love me."
And, in that case, Christ may well proclaim: "I never knew you; Depart from Me!"