Adam Clarke on John 11:27

Yea, Lord: I believe - ΠεπιϚευκα, I have believed. Either meaning that she had believed this for some time past, or that, since he began to teach her, her faith had been considerable increased; but verbs preter, in Greek, are often used to signify the present. Martha here acknowledges Christ for the Messiah promised to their fathers; but her faith goes no farther; and, having received some hope of her brother's present resurrection, she waited for no farther instruction, but ran to call her sister.