How can I know a person is spiritually mature?

Scripture tells us that the best sign of spiritual maturity in a Christian is a devoted desire to know and obey God’s word:

Matt. 7:24  “Therefore everyone who hears these words of Mine and acts on them, may be compared to a wise man who built his house on the rock.
Matt. 7:25 “And the rain fell, and the floods came, and the winds blew and slammed against that house; and yet it did not fall, for it had been founded on the rock.
Matt. 7:26 “Everyone who hears these words of Mine and does not act on them, will be like a foolish man who built his house on the sand.
Matt. 7:27 “The rain fell, and the floods came, and the winds blew and slammed against that house; and it fell — and great was its fall.”
 

Luke 8:20 And it was reported to Him, “Your mother and Your brothers are standing outside, wishing to see You.” 
Luke 8:21 But He answered and said to them, “My mother and My brothers are these who hear the word of God and do it.”
 

Luke 11:27  While Jesus was saying these things, one of the women in the crowd raised her voice and said to Him, “Blessed is the womb that bore You and the breasts at which You nursed.” 
Luke 11:28 But He said, “On the contrary, blessed are those who hear the word of God and observe it.”
 

John 14:23 Jesus answered and said to him, “If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our abode with him.
John 14:24 “He who does not love Me does not keep My words; and the word which you hear is not Mine, but the Father’s who sent Me.
 

1John 2:3  By this we know that we have come to know Him, if we keep His commandments. 
1John 2:4 The one who says, “I have come to know Him,” and does not keep His commandments, is a liar, and the truth is not in him; 
1John 2:5 but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him: 
1John 2:6 the one who says he abides in Him ought himself to walk in the same manner as He walked. 
 

When you encounter people claiming spiritual maturity and insight, consider their knowledge of God’s word and the conduct of their lives. If they are spiritually mature, they will demonstrate a sincere love for God’s word and a life that shows devotion to pleasing Christ through obedience. These are the marks of spiritual strength and maturity.