Jesus is saying absolutely that Christians shall not live to hoard money. Even prudence is against this, says Jesus. For where thy treasure is there will thy heart be also. That is, that upon which you concentrate will captivate your very heart. It will take first place in your life.
Money enslaves the miser.
Furthermore, in order to be a follower of Jesus it is necessary to have singleness of purpose, and money and God are absolutely incompatible as masters. Those who seek wealth, those who live for money, starve spiritually. Wealth-seeking really means seeking for power and security, and Christians rely for their power and their security not upon money but upon God. Christians in a positive way shall in simple trust rely upon God to supply the natural blessings which the need. God cares for even the birds, says Jesus.