Hadith: If only you relied on Allah the way you should, He would provide for you as He provides for birds; they set out hungry in the morning and return satiated in the evening

عن عمر بن الخطاب رضي الله عنه عن النبي صلى الله عليه وسلم أنه قال: «لو أنكم كنتم توَكَّلُون على الله حق توَكُّلِهِ لرزقكم كما يرزق الطير، تَغْدُو خِمَاصَاً، وتَرُوحُ بِطَاناَ».
[صحيح] - [رواه الترمذي وابن ماجه وأحمد]

‘Umar ibn al-Khattāb (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "If only you relied on Allah the way you should, He would provide for you as He provides for birds; they set out hungry in the morning and return satiated in the evening."
Sahih/Authentic. - [Ibn Maajah]

Explanation

This Hadīth guides us to rely on Allah, the Exalted, in all our affairs. True reliance is to depend on Allah in bringing forth what benefits and repelling what harms in all our worldly and religious affairs. Indeed, no one gives, withholds, harms, or benefits except Him, Glorified and Exalted. So one must utilize the available means that bring him benefit and repel harm together with reliance upon Allah: {And whosoever puts his trust in Allah, then He will suffice him} [Sūrat At-Talāq: 3} and {let all those that trust, put their trust in Him} [Sūrat Yūsuf: 67]. Whenever the slave does that, Allah will provide for him just as He provides for the birds, which set out in the morning feeling hungry then return in the evening with full bellies.