2מִי שֶׁהָיָה יוֹדֵעַ לַחֲבֵרוֹ עֵדוּת עַד שֶׁלֹּא נַעֲשָׂה חֲתָנוֹ וְנַעֲשָׂה חֲתָנוֹ. אוֹ שֶׁיָּדַע הָעֵדוּת וְהוּא פִּקֵּחַ וְאַחַר כָּךְ נִתְחָרֵשׁ. פָּתוּחַ וְנִסְתַּמֵּא אַף עַל פִּי שֶׁיָּכוֹל לְכַוֵּן מִדַּת הַקַּרְקַע שֶׁהוּא מֵעִיד בָּהּ וּמְסַיֵּם מְצָרֶיהָ. שָׁפוּי וְנִשְׁתַּטָּה. הֲרֵי זֶה פָּסוּל. אֲבָל אִם הָיָה יוֹדֵעַ לוֹ עֵדוּת עַד שֶׁלֹּא נַעֲשָׂה חֲתָנוֹ וְנַעֲשָׂה חֲתָנוֹ וּמֵתָה בִּתּוֹ. פִּקֵּחַ וְנִתְחָרֵשׁ וְחָזַר וְנִתְפַּקֵּחַ שָׁפוּי וְנִשְׁתַּטָּה וְחָזַר וְנִשְׁתַּפָּה פָּתוּחַ וְנִסְתַּמֵּא וְחָזַר וְנִתְפַּתֵּחַ כָּשֵׁר. זֶה הַכְּלָל כָּל שֶׁתְּחִלָּתוֹ וְסוֹפוֹ בְּכַשְׁרוּת אַף עַל פִּי שֶׁנִּפְסַל בֵּינְתַיִם כָּשֵׁר. תְּחִלָּתוֹ בְּפַסְלוּת אַף עַל פִּי שֶׁסּוֹפוֹ בְּכַשְׁרוּת פָּסוּל. לְפִיכָךְ מִי שֶׁהָיָה יוֹדֵעַ בְּעֵדוּת וְהוּא קָטָן וּבָא וְהֵעִיד בָּהּ כְּשֶׁהוּא גָּדוֹל אֵינָהּ כְּלוּם:
When a person knew of evidence concerning a colleague before he became his son-in-law, and then became his son-in-law, he is not acceptable. The same law applies if a person was in control of his senses and then became a deaf-mute, was able to see and became blind - even though he is aware of the measure of land concerning which he testifies and can define its boundaries, or was intellectually and emotionally sound and then lost control of his faculties. If, by contrast, a person knew of evidence concerning a colleague before he became his son-in-law, became his son-in-law, and then that colleague's daughter died, the witness is acceptable. Similar laws apply if a person was in control of his senses, became a deaf-mute, and then regained control of his senses, was intellectually and emotionally sound, lost control of his faculties, and then regained control of them, or was able to see, became blind, and then regained his sight. The general principle is: Whenever a person is an acceptable witness at the initial and the final stages, he is acceptable even though in the interim, he was not acceptable as a witness. If, however, initially he is unacceptable, even though ultimately, he would be acceptable, he is disqualified. Therefore when a person is aware of evidence as a child, it is of no consequence for him to testify with regard to it when he attains majority.