What are earthly props?

I have a friend who works a nation-wide ministry. She sends out a newsletter to let us know what is going on in her life. This month she sent a devotional she heard from her boss this month. I needed it. Maybe you do to.
Here is the verse:
Psalm 131

A song of ascents. Of David.  ¹ My heart is not proud, LORD,
   my eyes are not haughty;
I do not concern myself with great matters
   or things too wonderful for me.
² But I have calmed and quieted myself,
   I am like a weaned child with its mother;
   like a weaned child I am content.
 ³ Israel, put your hope in the LORD
   both now and forevermore.

This is the devotional from her boss:

"Charles Spurgeon said about this passage, “Remember that where your treasure is your heart will go—and if that treasure is taken away, your heart must ache,” if you’re leaning on or depending on things other than the Lord. He said, “The man who depends alone upon his God and whose expectation is from Him, has not half the occasions for trouble that he has who is leaning here and leaning there, and leaning in 50 places! For each earthly prop will be the cause or occasion of distress at some time or other.”

You say, “What are earthly props?”

·         It may be your husband you’re looking to to satisfy your needs.

·         It may be your child.

·         It may be your job.

·         It may be shopping.

·         It may be food.

·         It may be friends.

Whatever you’re leaning on, whatever you’re looking to to meet the deepest needs of your heart, will be the cause or the occasion of distress at some time or other—unless you’re leaning on the Lord. He will never fail you. He will never distress you. He will never let you down. "

Have a good day!