Sometimes phrases like "Jesus loves you" and "Everything will be okay" are more efficient than long texts telling me this exact same things in a more extended version. Just like sometimes, long paragraphs that will explain why, how and when Jesus loves me or why, how and when will everything be okay are more efficient than short phrases.
The thing is: none of these are wrong and both are a must! The only wrong thing is to have just one of these "sources", because when the darkness come and the worst feelings surface to swallow us we may need both; one for a immediate good response to the bad situation and the other to reaffirm that good response and keep us sane!
But the most important thing to have above all these 2 is the scriptures, God's words written in the bible. Those are the most effective words to read and meditate on. They're directly from God and the message on them are very clear about anxiety and sadness. He recognizes these feelings and tell us how to overcome them through Him!
Never forget to read your bible, never forget to meditate on them, never forget these words and never stop letting this truth take root in your heart! Ask the Holy spirit to make in you a good soil so His words will grow well! (That's on Luke 8.4-15. Here's verse 15: "And what about the seed that fell on the good ground? That is like the people who hear God’s teaching with a good, honest heart. They obey it and patiently produce a good crop. (ERV)").
Well that's pretty much a thought that went through my mind today. Hope it's something useful!