At Matthew 14:25-28 we read:
And early in the morning he came walking toward them on the sea. But when the disciples saw him walking on the sea, they were terrified, saying, "It is a ghost!" And they cried out in fear. But immediately Jesus spoke to them and said, "Take heart, it is I; do not be afraid." Peter answered him, "Lord, if it is you, command me to come to you on the water.
I like to believe that the saying of Peter, "if it is you," is a weak translation of the original text. Only after getting the confirmation that he was looking at Jesus, and not a ghost, does Peter place his request. So there is no point in his using the 'if' word.
I wish to know if there are other forms in which the original text could have been translated into, say, "now that it is you." What do the Catholic interpretations say on such a perspective?