1 John 5:8

τὸ ὕδωρ καὶ τὸ αἶμα. These of course have the same meaning as before; Christ’s Baptism and Death. “The real value of our Lord’s baptism and His death may be estimated by supposing that neither had taken place, and that our Lord had appeared on His mission without openly confessing His mission from God in submitting to the baptism of John; or that He had died quietly, as other men die” (Jelf).

καὶ οἱ τρεῖς εἰς τὸ ἕν εἰσιν. Literally, and the three are (united) into the one; or, are for the one object of establishing this truth. This may mean either that they are joined so as to become one witness, or that they co-operate in producing one result. “The trinity of witnesses furnish one testimony”. ‘To be one’ (ἕν εἶναι) occurs John 10:30; John 17:11; John 17:21-22, and (εἶς ἐστε) Galatians 3:28 : ‘into one’ (εἰς ἕν) occurs John 11:52; John 17:23 : but ‘to be into one’ or ‘to be into the one’ occurs nowhere else in N.T. Τὸ ἕν here has been made into an argument for the genuineness of 1 John 5:7. It is said that ‘the one’ plainly implies that ‘one’ has preceded. But this lands us in absurdity by making ‘one’ in 1 John 5:8 mean the same as ‘one’ in 1 John 5:7. ‘One’ in 1 John 5:7. means ‘one Substance’, the ‘Unity in Trinity’. But what sense can ‘The spirit, the water, and the blood agree in the Unity in Trinity’ yield?