Philippians  2:11  Paul said; every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.

 

Hebrews 11:1 Now faith is the substance of things hoped for, the evidence of things not seen.

 

Romans 10:10 For with the heart man believes unto righteousness; and with the mouth confession is made unto salvation. Believe, confess, receive salvation

 

Acts 8:36-39 The eunuch said, See, here is water; what does hinder me to be baptized? Philip said; if you believe with all your heart, you might. And he answered and said; I believe that Jesus Christ is the Son of God.

Was the eunuch saved at that instant? There was no sinner's prayer; there was merely the statement of belief from the heart!

IMHO I think that he was. When we receive Jesus as Lord and Savior we become his priests.  Are not the priests washed in the waters before they go in to worship before the Lord? Is that not what baptizm represents as well as death [in Christ], burial [buried in Christ] and resurrection [raised in Christ]? 

Galatians 2:20 "I am crucified with Christ: nevertheless I live; yet not I, but Christ lives in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me."

jfh

And Philip commanded the chariot to stand still: and they both went down into the water, Philip and the eunuch; and he baptized him. And when they were come up out of the water, the Spirit of the Lord caught away Philip, that the eunuch saw him no more: and he went on his way rejoicing.