לֹא־תִרְאֶה֩ אֶת־חֲמ֨וֹר אָחִ֜יךָ א֤וֹ שׁוֹרוֹ֙ נֹפְלִ֣ים בַּדֶּ֔רֶךְ וְהִתְעַלַּמְתָּ֖ מֵהֶ֑ם הָקֵ֥ם תָּקִ֖ים עִמּֽוֹ׃ (ס)
你若看見你弟兄的驢或牛跌倒在路上，不可轉眼不顧，務要幫助他把牠們扶起來。
Mekhilta DeRabbi Yishmael
"help shall you help with him": What is the intent of this? From (Devarim 22:4) "Lift up shall you lift up with him" I might think that only loading (is commanded). Whence do I derive (the same for) unloading? From "help shall you help with him." R. Yoshiyah says: In both instances Scripture speaks of unloading. This tells me only of unloading. Whence do I derive (the same for) loading. It follows a fortiori, viz.: If unloading, which he (the owner of the animal) can do by himself, the other is commanded to assist him with, how much more so loading, which he cannot do by himself! Scripture speaks of the less obvious instance to derive therefrom the more obvious (by a fortiori reasoning)
Sifrei Devarim
(Devarim 22:4) "You shall not see the ass of your brother or his ox fallen on the way and ignore them; lift up shall you lift up with him." "You shall not see the ass of your brother": This is a negative commandment. And elsewhere it is written (Shemoth 23:5) "If you see, etc.": That is a positive commandment.