A Christian is anyone who carries God's love to his neighbor (John 13:34-35). The conveyance of God's love to neighbor identifies a Christian (Revelation 3:15-17). Nothing else.
In fact, it is the only way to identify a servant of God of any religion (Mark 10:21).
You can be baptized and confirmed. You can hold in your head the most orthodox of Christian doctrine. You can go to Mass daily. You can confess your sins regularly. You can pray all day long. However, if you are not carrying God's love to your neighbor, you are a fraud. You are masquerading as a Christian but you are not (Matthew 19:21). You are a pretender. You are neither hot nor cold but lukewarm so, at the end, God will spew you out of his mouth (Revelation 3:15-17).
The holy pipeline that carries God's love for us starts at the heart of God the Father. From there, it proceeds to God the Son. Through the bloody wounds we opened in the body of the Son of God while he was human, alive, tender, vulnerable and our guest here upon the earth, God's love for us flows. The bloody wounds are conduits through which the river of God's love flows from heaven to earth. By torturing and killing him, we could have, to say the least, pissed God off. The sin of sins that we committed against the very person of the Son of God ought to have triggered God's revenge reflex bringing the brunt of his furious wrath down upon our fragile heads. But God's thoughts are not our thoughts; God's ways are not our ways (Isaiah 55:8-9). Unexpectedly, God continued to love us nonetheless. We tortured and killed him, yet, he continued to love us nonetheless. That His love for us survived the gruesome baptism into which we immersed him (Matthew 3:13-17) communicates to us the message that divinity is love - pure love unadulterated by any of the impurities and defects that adulterate human love. The survival of his love for us puts into our hands a guaranty that his love for us is genuine. If his love for us were counterfeit, it would have faded as we tortured him and died when we killed him. But it did not. The evil we did to the Son of God did not extinguish his love for us or reduce it by even the slightest degree. The next segment of the holy pipeline presented to God, what seems to us, an impossible, insurmountable construction problem. Between then and there and here and now is impassable gap - a gap in time of more than two thousand years and a gap in space of half way around the world. We opened the bloody wounds in the boondocks of time and space. The event was inconspicuous, anonymous and remote. The question was how to perpetuate and propagate its memory through time and space. God decided that a memorial was needed to keep the attention of the children of Adam and Eve focused on the bloody wounds. God did not want to establish an ordinary, conventional, run-of-the-mill memorial. God did not want a firefly. God wanted a fire - a blazing, raging, engaging bonfire to match the bonfire of love that we see when we look through the bloody wounds we opened in the body of the Son of God to his most sacred heart. Any inferior memorial just would not do. God reviewed the candidates for a memorial - words, a reenactment, a work of art, and other types of representations depicting our opening of the bloody wounds. It would be too cruel to ask the Son of God to let us impale Him on the Cross - to repeat His sacrifice at Calvary anew - for each successive generation and, within a generation, from place to place (Luke 16:19-31). One Calvary - one guarantee of His love for us - was enough. Duplicate guarantees would be superfluous. From God's review of the candidates for a memorial, God realized that the any representations made by human hands of the bloody wounds would be inferior to the bloody wounds themselves. Therefore, God decided that the memorial had to be nothing less than the bloody wounds themselves. So God did the impossible. God created a time machine. God uprooted the bloody wounds from their foundation in time and space, made them portable and created a vehicle to carry them to us in the present. The vehicle that carries the bloody wounds of the Son of God to us is the Mass. At Mass, the physics of time and space are suspended so that God's love for us can pass through the hands of a priest and into the body and the blood of the most Holy Eucharist during Mass. Thence, God's love passes to us.
The end.
Wait.
Not so fast.
Many think that this is the end of the journey of God's love. This, however, is not the end of journey. There is one more leg of the journey. And, it is the last leg of the journey that matters. All else is geared to make the last leg of the journey possible. The last leg of the journey occurs when we pass God's love of us to our neighbor.
God's love for us passes to us
not for us to keep for ourselves
but for us to give away, as he gave it away, to our neighbors.
We cross the boundary that separates potential Christians from full fledged Christians only by delivering God's love to our neighbors.