Imam Maalik مالك بن أنس بن مالك بن أبي عامر · The Book of Shortening the Prayer When Traveling

"I said to 'Umar bin Al-Khattab: 'There is no sin on you if you shorten salah and if you fear that the disbelievers may put you in trial (attack you). But now the people are safe.' 'Umar said: 'I wondered the same thing, so I asked the Messenger of Allah (ﷺ) about that and he said: This is a favor from Allah (SWT) to you, so accept His favor."