‘For which reason, putting away all filthiness and overflowing of wickedness, receive with meekness the implanted word, which is able to save your souls.'
‘For which reason' may apply to the previous verse, with the emphasis being on the fact that rather than behaving angrily they are to receive the implanted word with a meek and gentle spirit, or it may look back to the whole passage and the fact that they are dealing with heavenly and glorious Creator. In this case the emphasis is on the need to do away with sin and all that offends God, and this would fit well with James 1:13-15.
But either way it is important that filthiness and overflowing of wickedness should be ‘put away'. It is a call to repentance in the light of the new revelation (compare ‘repent and believe in the good news' - Mark 1:16). They are to ‘take off, as they would a garment, all that is wrong and impure, all that defiles, including their false words, responding rather to the implanted word of truth, and putting it on in the way that they live their lives. Compare Paul's ‘put off the old man -- which is corrupt through deceitful lusts -- and put on the new which is created after the likeness of God in righteousness and true holiness' (Ephesians 4:22-24).
‘Overflowing (excess) of wickedness.' This may refer to the wickedness that still remains even after their first reception of the word of truth which has now also to be put off (as he will go on to demonstrate), or it may refer to the way in which wickedness can flow up from our lives, something which must be fully dealt with.
‘The implanted word.' And instead of these things they are to delight in God's word, the powerful word that He has implanted within them (James 1:18), receiving it and responding to it, for it is able to save their souls. It is like a seed planted in their hearts which grows and flourishes (Matthew 13:18-23). It will bring them to eternal life (James 1:12), to the eternal Kingly Rule (Matthew 13:43). This ‘saving of souls' is important to James, for he will close off his letter with the idea (James 5:20). It is what all their trials are intended to achieve. The idea here of ‘saving' is not of once for all salvation, that occurred when they were begotten of God by the word of truth, but of the constant need to experience God's saving power so that His end might be achieved. They are undergoing a process of spiritual healing, of ‘sanctification'. They are being made like Him as a result of the carrying out of His will (Romans 8:29; Ephesians 1:4; 1 John 3:2-3). They are being changed from glory into glory (2 Corinthians 3:18). God is at work in them to will and to do of His good pleasure (Philippians 2:13). And they are to take heed and receive the implanted word, which, like healing medicine, will restore them and make them whole.
‘Receive with meekness (that is, with ‘a teachable spirit').' The word here is describing the quality of the man whose feelings and emotions are under perfect control and who is ready to learn. There will be no harsh words.