看在X的面子上: out of regard for X
【高139】口语格式 / fixed patterns
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
看在 X 的面子上 means "out of regard for X, as a favour to X". X is the person (a relative, a superior, a friend, or the listener himself: 看在你的面子上) to whom one grants a favour: the speaker does what he would not otherwise do, or lets something go. The frame is fixed: 看在 + person + 的面子上, and this clause comes before the main verb: 看在老朋友的面子上，这次就算了.
面子 ("face", a person's standing and honour in the eyes of others) explains it: you give way, but you give way to X, not to the other side. That is how one drops a position without losing face. The main clause is usually a concession: 答应, 原谅, 算了, 让步, 帮忙, 同意.
It is a spoken phrase, common in daily life and in business alike. Close variants: 看在……的份上 (same sense) and 给……面子 ("to show respect to").
Examples
我是看在她的面子上才答应的。
Wǒ shì kàn zài tā de miànzi shang cái dāying de.I only agreed out of regard for her.
看在老朋友的面子上，这次就算了。
Kàn zài lǎo péngyou de miànzi shang, zhè cì jiù suàn le.For the sake of an old friend, let's drop it this time.
三位客人看在老人的面子上又坐下了。
Sān wèi kèrén kàn zài lǎorén de miànzi shang yòu zuò xià le.The three guests sat down again out of regard for the old man.
要不是看在你的面子上，这么低的价钱我才不会卖呢。
Yàobùshì kàn zài nǐ de miànzi shang, zhème dī de jiàqián wǒ cái bú huì mài ne.If it were not for you, I would never sell at such a low price.
看在王经理的面子上，银行同意再给我们一个月时间。
Kàn zài Wáng jīnglǐ de miànzi shang, yínháng tóngyì zài gěi wǒmen yí ge yuè shíjiān.Out of regard for Manager Wang, the bank agreed to give us another month.
他平时很少让步，可是看在老同学的面子上，还是把价格降低了一些。
Tā píngshí hěn shǎo ràngbù, kěshì kàn zài lǎo tóngxué de miànzi shang, háishi bǎ jiàgé jiàngdī le yìxiē.He rarely gives way, but for the sake of an old classmate he did bring the price down a little.
Common mistakes
✗ 我看在面子上答应了。 → ✓ 我看在她的面子上答应了 (name the person: 看在 + X + 的面子上).
✗ 看在你的面子，我答应了。 → ✓ 看在你的面子上，我答应了 (the frame ends in 上).