They were anxious about things they ought not be anxious about. Jesus said to stop that ​ — and for good reason.
لِذٰلِكَ قَالَ لَهُمْ فِي ٱلْمَوْعِظَةِ عَلَى ٱلْجَبَلِ :‏ « لَا تَحْمِلُوا بَعْدُ هَمَّ نُفُوسِكُمْ » .‏